SemOpenAlex |

SemOpenAlex

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2020199777> ?p ?o ?g. }

Showing items 1 to 100 of ±124 with 100 items per page.

W2020199777 endingPage "23595" @default.
W2020199777 startingPage "23589" @default.
W2020199777 abstract "We previously reported that MOLT-3 human lymphocyte-like leukemia cells adhere to tissue-type transglutaminase (tTG) through the integrin α4β1. We now report that G-361 human melanoma cells also adhere to tTG, although they do not express α4β1. G-361 cells utilize two additional integrins, α9β1 and α5β1 to adhere to tTG. Furthermore, blood coagulation factor XIII (FXIII), another member of the transglutaminase family that is highly homologous to tTG, and propolypeptide of von Willebrand factor (pp-vWF) also promoted cell adhesion through α9β1 or α4β1 in G-361 or MOLT-3 cells, respectively. In the case of pp-vWF, α9β1 and α4β1both bind to the same site, comprised of 15 amino acid residues and designated T2–15. Moreover, SW480 human colon cancer cells stably transfected to express α9β1, but not mock transfectants, adhered to tTG, FXIII, pp-vWF, and T2–15/bovine serum albumin conjugate. These data identify tTG, FXIII, and pp-vWF as shared ligands for the integrins α9β1 and α4β1. This report is the first to unambiguously show that these two integrins share the same cell adhesion site within one protein and provides strong support for classifying α9β1- and α4-integrins as functionally related members of an integrin subfamily. We previously reported that MOLT-3 human lymphocyte-like leukemia cells adhere to tissue-type transglutaminase (tTG) through the integrin α4β1. We now report that G-361 human melanoma cells also adhere to tTG, although they do not express α4β1. G-361 cells utilize two additional integrins, α9β1 and α5β1 to adhere to tTG. Furthermore, blood coagulation factor XIII (FXIII), another member of the transglutaminase family that is highly homologous to tTG, and propolypeptide of von Willebrand factor (pp-vWF) also promoted cell adhesion through α9β1 or α4β1 in G-361 or MOLT-3 cells, respectively. In the case of pp-vWF, α9β1 and α4β1both bind to the same site, comprised of 15 amino acid residues and designated T2–15. Moreover, SW480 human colon cancer cells stably transfected to express α9β1, but not mock transfectants, adhered to tTG, FXIII, pp-vWF, and T2–15/bovine serum albumin conjugate. These data identify tTG, FXIII, and pp-vWF as shared ligands for the integrins α9β1 and α4β1. This report is the first to unambiguously show that these two integrins share the same cell adhesion site within one protein and provides strong support for classifying α9β1- and α4-integrins as functionally related members of an integrin subfamily. vascular cell adhesion molecule-1 tissue-type transglutaminase blood coagulation factor XIII propolypeptide of von Willebrand factor monoclonal antibody bovine serum albumin Integrins are a family of heterodimeric transmembrane receptors that mediate cell-extracellular matrix and cell-cell interactions and play important roles in a wide variety of cellular events (1Hynes R.O. Cell. 1987; 48: 549-554Abstract Full Text PDF PubMed Scopus (3082) Google Scholar, 2Hemler M.E. Immunol. Today. 1988; 9: 109-113Abstract Full Text PDF PubMed Scopus (258) Google Scholar, 3Akiyama S.K. Nagata K. Yamada K.M. Biochim. Biophys. Acta. 1990; 1031: 91-110Crossref PubMed Scopus (231) Google Scholar, 4Albelda S.M. Buck C.A. FASEB J. 1990; 4: 2868-2880Crossref PubMed Scopus (1622) Google Scholar, 5Ruoslahti E. J. Clin. Invest. 1991; 87: 1-5Crossref PubMed Scopus (1478) Google Scholar, 6Hynes R.O. Cell. 1992; 69: 11-25Abstract Full Text PDF PubMed Scopus (8966) Google Scholar). Each integrin is composed of noncovalently associated α and β subunits, and the combination of α and β subunits generates many different receptors with different ligand specificity.Integrin α subunits can be grouped into subfamilies based on sequence similarity, and these subfamilies generally define integrins that share common ligands. Thus, α subunits can be divided into five groups (6Hynes R.O. Cell. 1992; 69: 11-25Abstract Full Text PDF PubMed Scopus (8966) Google Scholar, 7Camper L. Hellman U. Lundgren-Akerlund E. J. Biol. Chem. 1998; 273: 20383-20389Abstract Full Text Full Text PDF PubMed Scopus (202) Google Scholar, 8Velling T. Kusche-Gullberg M. Sejersen T. Gullberg D. J. Biol. Chem. 1999; 274: 25735-25742Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar): the first group (α1, α2, α10, and α11) recognizes collagen, the second group (α3, α6, and α7) recognizes laminin, the third group (α5, α8, αv, and αIIb) recognizes RGD-containing sequences, and the fourth group (αL, αM, αX, and αD) recognizes ICAM-1. α4 and α9 are the only members of the fifth group (9Palmer E.L. Ruegg C. Ferrando R. Pytela R. Sheppard D. J. Cell Biol. 1993; 123: 1289-1297Crossref PubMed Scopus (215) Google Scholar). Somewhat surprisingly, the initial ligands identified for α9 and α4-containing integrins did not appear to overlap. Thus, for example, the integrin α4β1 was found to recognize fibronectin (10Guan J.L. Hynes R.O. Cell. 1990; 60: 53-61Abstract Full Text PDF PubMed Scopus (518) Google Scholar, 11Mould A.P. Wheldon L.A. Komoriya A. Wayner E.A. Yamada K.M. Humphries M.J. J. Biol. Chem. 1990; 265: 4020-4024Abstract Full Text PDF PubMed Google Scholar) and the vascular cell adhesion molecule-1 (VCAM-1)1 as ligands (12Chuluyan H.E. Osborn L. Lobb R. Issekutz A.C. J. Immunol. 1995; 155: 3135-3144PubMed Google Scholar), whereas the integrin α9β1 was reported to recognize tenascin-C, (13Yokosaki Y. Palmer E.L. Prieto A.L. Crossin K.L. Bourdon M.A. Pytela R. Sheppard D. J. Biol. Chem. 1994; 269: 26691-26696Abstract Full Text PDF PubMed Google Scholar, 14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar), and osteopontin (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar, 16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). However, recently Bayless et al. (17Bayless K.J. Meininger G.A. Scholtz J.M. Davis G.E. J. Cell Sci. 1998; 111: 1165-1174Crossref PubMed Google Scholar) reported that α4β1 recognizes osteopontin as a ligand, and Taooka et al. (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar) reported that α9β1 recognizes VCAM-1. It thus appears that the α4β1- and α9β1-integrins, like other integrins that are related based on α subunit sequence homology, do share at least some common ligands.In the present study, we demonstrate that three additional proteins are ligands for both α9β1 and α4β1. The first is a tissue-type transglutaminase (tTG). This protein belongs to a family of transglutaminases (EC 2.3.2.13) that catalyze ε-(γ-glutamyl)lysine cross-link formation between specific substrate proteins (19Folk J.E. Finlayson J.S. Adv. Protein Chem. 1977; 31: 1-133Crossref PubMed Scopus (782) Google Scholar, 20Folk J.E. Annu. Rev. Biochem. 1980; 49: 517-531Crossref PubMed Scopus (869) Google Scholar, 21Lorand L. Conrad S.M. Mol. Cell Biochem. 1984; 58: 9-35Crossref PubMed Scopus (657) Google Scholar) and are distributed widely in various tissues. The second is blood coagulation factor XIII (FXIII). This protein is also a member of the transglutaminase family and has an important role in the final stage of the blood coagulation cascade. The last is the propolypeptide of von Willebrand factor (pp-vWF). This protein is obtained from a large precursor of von Willebrand factor by specific cleavage during biosynthesis and is stored in granules of both endothelial cells and platelets (22Verweij C.L. Diergaarde P.J. Hart M. Pannekoek H. EMBO J. 1986; 5: 1839-1847Crossref PubMed Scopus (186) Google Scholar, 23Wagner D.D. Annu. Rev. Cell Biol. 1990; 6: 217-246Crossref PubMed Google Scholar). In the case of pp-vWF, we have mapped the recognition sequence for both integrins to the same cell adhesion site, a 15-residue linear sequence that we have previously shown is required for α4β1-mediated adhesion to this protein (24Isobe T. Hisaoka T. Shimizu A. Okuno M. Aimoto S. Takada Y. Saito Y. Takagi J. J. Biol. Chem. 1997; 272: 8447-8453Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar).DISCUSSIONPrevious reports identified three ligands for the integrin α9β1, VCAM-1 (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar), tenascin-C (13Yokosaki Y. Palmer E.L. Prieto A.L. Crossin K.L. Bourdon M.A. Pytela R. Sheppard D. J. Biol. Chem. 1994; 269: 26691-26696Abstract Full Text PDF PubMed Google Scholar, 14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar), and osteopontin (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar, 16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). In this report, we describe three additional ligands, tTG, FXIII, and pp-vWF. Among the previously identified α9β1 ligands, VCAM-1 and osteopontin have both been reported to be recognized by both α9β1 and the structurally related integrin α4β1 (17Bayless K.J. Meininger G.A. Scholtz J.M. Davis G.E. J. Cell Sci. 1998; 111: 1165-1174Crossref PubMed Google Scholar, 35Elices M.J. Osborn L. Takada Y. Crouse C. Luhowskyj S. Hemler M.E. Lobb R.R. Cell. 1990; 60: 577-584Abstract Full Text PDF PubMed Scopus (1508) Google Scholar). In this report, we show that each of the three new α9β1 ligands we identified is also a ligand for α4β1.Although it might seem reasonable to assume that α9β1 and α4β1recognize the same adhesive sites in shared ligands, this is not necessarily the case. There are numerous examples of different integrins recognizing distinct sites in the same ligand. For example, at least five integrins can recognize the third fibronectin type III repeat in tenascin-C as a ligand, but four of them recognize the RGD site in the F-G loop, whereas α9β1 clearly recognizes a different sequence, AEIDGIEL, in the B-C loop present on the same face of the protein (14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar). Similarly, both the integrins αvβ3 and α9β1recognize a thrombin-cleaved N-terminal fragment of osteopontin as a ligand (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar), but αvβ3 binds to an RGD site, whereas α9β1 binds to the adjacent sequence, SVVYGLR (16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). In fact, prior to the present report, there was no definitive evidence that α9β1 and α4β1 could recognize the same site in a shared ligand. The evidence presented in this report that both integrins recognize the same linear peptide, T2–15, within pp-vWF is to our knowledge the first conclusive evidence that these integrins can recognize the same cell adhesion site within one molecule (TableI). Interestingly, the sequence of this peptide, DCQDHSFSIVIETVQ, bears little resemblance to the previously identified α9β1-recognition sequences in tenascin-C and osteopontin. This observation provides additional evidence that α9β1 can recognize a surprisingly broad array of adhesive ligands. Taken together, the accumulated evidence that α9β1 and α4β1 share five ligands and, at least in one instance, recognize the same linear peptide within a ligand confirms the utility of α subunit sequence comparisons for predicting ligand binding specificity of integrin heterodimers.Table IVarious adhesion ligands that are recognized by α9β1 and/or α4β1 integrinα9β1α4β1Fibronectin×○(ILDV)VCAM-1○○(IDSP)Tenascin-C○(AEIDGIEL)?Ostcopontin○(SVVYGLR)○pp-vWF○○(DCQDHSFSIVIETVQ)tTG○○FXIII○○Adhesion to various ligands is illustrated according to the results obtained by ourselves and other investigators. ○, recognition of the integrin; ×, no recognition of the integrin; ?, no determination. The proposed essential cell adhesion sequences are shown in parentheses. Open table in a new tab The interaction between tTG and integrins is likely to be biologically significant. tTG directly binds to a number of components of the extracellular matrix, including osteopontin and tenascin-C, where it plays an important role in matrix protein cross-linking. A recent report demonstrated that tTG bound to the integrins α5β1 and αIIbβ3within the secretory apparatus prior to appearance of the integrins on the cell surface, thereby suggesting a mechanism for localization of tTG to its extracellular targets (32Akimov S, A. Krylov D. Fleischman L.F. Belkin A.M. J. Cell Biol. 2000; 148: 825-838Crossref PubMed Scopus (414) Google Scholar). Furthermore, the same study showed that the interaction of integrins with tTG enhanced cell attachment and spreading on fibronectin. The findings in the present study greatly expand the complexity of these potential interactions and suggest that similar mechanisms could be involved in cellular interactions with additional sites in fibronectin (e.g. the CS-1 site) and with a broad array of extracellular matrix ligands. Recently, as noted above, Akimov and co-workers reported that tTG could interact with several members of the integrin family, including α5β1 (as we also report in the current study), but also α1β1, α3β1, αvβ3 and αIIbβ3 (32Akimov S, A. Krylov D. Fleischman L.F. Belkin A.M. J. Cell Biol. 2000; 148: 825-838Crossref PubMed Scopus (414) Google Scholar). Interestingly, the report by Akimov et al. demonstrated that the related transglutaminase family member, FXIII, was not a ligand for α5β1, and thus suggested that the interactions between integrins and transglutaminases was specific for tTG. Although that report and this one both described interactions between α5β1 and tTG, there were several substantial differences. For example, Akimov et al. found no effect of either GRGDSP peptide or anti-β1 antibody on the interaction between tTG and integrins they describe, whereas in this report we found that GRGDSP completely eliminated the residual adhesion of G-361 cells to tTG once α9β1-mediated adhesion was inhibited, and we also found complete inhibition with anti-β1 antibody. Furthermore, we found no role for integrins other than α4β1, α5β1, or α9β1 in the adhesion of MOLT-3 or G-361 cells to tTG. We have checked the expression of various integrin subunits other than those shown in Fig. 2. As is clearly depicted in Fig. 10, G-361 cells also expressed α2, α3, α6, and αvβ3. MOLT-3 cells, however, did not express these integrins substantially. Results obtained with G-361 cells further substantiate the notion that these integrins are not involved in the adhesion of G-361 cells to tTG. There are several possible explanations for these differences. One obvious difference is that Akimov et al. were examining the effects of tTG on cell adhesion to the 42-kDa fragment of fibronectin, and in their case the tTG was supplied to integrins within the secretory apparatus of the same cell, whereas the present study examined adhesion to immobilized tTG. Under the conditions examined by Akimov et al., it is conceivable that blocking antibodies and GRGDSP peptide would not be able to displace already bound tTG, whereas these reagents were perfectly capable of binding to unligated integrin under the conditions used in the present study, thereby blocking subsequent interactions with tTG. Such an explanation is plausible because it is often more difficult to detach already adherent cells with integrin-blocking reagents than to block the attachment of suspended cells. Alternatively, the WI-38 cells and HEL cells used by Akimov et al. and the MOLT-3 cells and G-361 cells used in the present study could interact with tTG through different mechanisms.The results of the present study also clearly demonstrate that although α5β1 is not a receptor for inactive FXIII, both α4β1 and α9β1 are. These findings appear to differ from our previous report suggesting that α5β1 did contribute to adhesion of TIG-1 cells to FXIII. However, the adhesion observed in those experiments required that the FXIII be activated. The results of the present study confirm that α5β1 on G-361 cells can also mediate adhesion to activated FXIII (data not shown). We are uncertain whether the requirement for activation in this case is due to a conformational change in FXIII upon activation that unmasks an α5β1 binding site or to a requirement for enzymatic activity to induce α5β1-mediated adhesionThe interaction of α4β1 and α9β1 with FXIII could be biologically significant. Both α4β1 and α9β1 are highly expressed on specific populations of leukocytes, where they play a prominent role in transendothelial leukocyte migration. As a member of the coagulation cascade, FXIII is likely to be enriched at sites of vascular injury and inflammation, where its interaction with α4β1 and α9β1could promote leukocyte extravasation.We speculated previously about the function of pp-vWF as an emergency tag for targeting of α4β1-expressing leukocytes, together with VCAM-1, to sites of inflammation and injury (24Isobe T. Hisaoka T. Shimizu A. Okuno M. Aimoto S. Takada Y. Saito Y. Takagi J. J. Biol. Chem. 1997; 272: 8447-8453Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar). Such a mechanism would be expected to be most relevant to lymphocytes, monocytes, and eosinophils, all of which express high levels of α4β1 (36Bochner B.S. Luscinskas F.W. Gimbrone Jr., M. Newman W. Sterbinsky S.A. Derse-Anthony C.P. Klunk D. Schleimer R.P. J. Exp. Med. 1991; 173: 1553-1557Crossref PubMed Scopus (577) Google Scholar). The recent report by Taooka et al. (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar) that human neutrophils express α9β1 and utilize this integrin for migration on VCAM-1 and through activated endothelial monolayers extends this possible function to all populations of circulating leukocytes. Integrins are a family of heterodimeric transmembrane receptors that mediate cell-extracellular matrix and cell-cell interactions and play important roles in a wide variety of cellular events (1Hynes R.O. Cell. 1987; 48: 549-554Abstract Full Text PDF PubMed Scopus (3082) Google Scholar, 2Hemler M.E. Immunol. Today. 1988; 9: 109-113Abstract Full Text PDF PubMed Scopus (258) Google Scholar, 3Akiyama S.K. Nagata K. Yamada K.M. Biochim. Biophys. Acta. 1990; 1031: 91-110Crossref PubMed Scopus (231) Google Scholar, 4Albelda S.M. Buck C.A. FASEB J. 1990; 4: 2868-2880Crossref PubMed Scopus (1622) Google Scholar, 5Ruoslahti E. J. Clin. Invest. 1991; 87: 1-5Crossref PubMed Scopus (1478) Google Scholar, 6Hynes R.O. Cell. 1992; 69: 11-25Abstract Full Text PDF PubMed Scopus (8966) Google Scholar). Each integrin is composed of noncovalently associated α and β subunits, and the combination of α and β subunits generates many different receptors with different ligand specificity. Integrin α subunits can be grouped into subfamilies based on sequence similarity, and these subfamilies generally define integrins that share common ligands. Thus, α subunits can be divided into five groups (6Hynes R.O. Cell. 1992; 69: 11-25Abstract Full Text PDF PubMed Scopus (8966) Google Scholar, 7Camper L. Hellman U. Lundgren-Akerlund E. J. Biol. Chem. 1998; 273: 20383-20389Abstract Full Text Full Text PDF PubMed Scopus (202) Google Scholar, 8Velling T. Kusche-Gullberg M. Sejersen T. Gullberg D. J. Biol. Chem. 1999; 274: 25735-25742Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar): the first group (α1, α2, α10, and α11) recognizes collagen, the second group (α3, α6, and α7) recognizes laminin, the third group (α5, α8, αv, and αIIb) recognizes RGD-containing sequences, and the fourth group (αL, αM, αX, and αD) recognizes ICAM-1. α4 and α9 are the only members of the fifth group (9Palmer E.L. Ruegg C. Ferrando R. Pytela R. Sheppard D. J. Cell Biol. 1993; 123: 1289-1297Crossref PubMed Scopus (215) Google Scholar). Somewhat surprisingly, the initial ligands identified for α9 and α4-containing integrins did not appear to overlap. Thus, for example, the integrin α4β1 was found to recognize fibronectin (10Guan J.L. Hynes R.O. Cell. 1990; 60: 53-61Abstract Full Text PDF PubMed Scopus (518) Google Scholar, 11Mould A.P. Wheldon L.A. Komoriya A. Wayner E.A. Yamada K.M. Humphries M.J. J. Biol. Chem. 1990; 265: 4020-4024Abstract Full Text PDF PubMed Google Scholar) and the vascular cell adhesion molecule-1 (VCAM-1)1 as ligands (12Chuluyan H.E. Osborn L. Lobb R. Issekutz A.C. J. Immunol. 1995; 155: 3135-3144PubMed Google Scholar), whereas the integrin α9β1 was reported to recognize tenascin-C, (13Yokosaki Y. Palmer E.L. Prieto A.L. Crossin K.L. Bourdon M.A. Pytela R. Sheppard D. J. Biol. Chem. 1994; 269: 26691-26696Abstract Full Text PDF PubMed Google Scholar, 14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar), and osteopontin (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar, 16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). However, recently Bayless et al. (17Bayless K.J. Meininger G.A. Scholtz J.M. Davis G.E. J. Cell Sci. 1998; 111: 1165-1174Crossref PubMed Google Scholar) reported that α4β1 recognizes osteopontin as a ligand, and Taooka et al. (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar) reported that α9β1 recognizes VCAM-1. It thus appears that the α4β1- and α9β1-integrins, like other integrins that are related based on α subunit sequence homology, do share at least some common ligands. In the present study, we demonstrate that three additional proteins are ligands for both α9β1 and α4β1. The first is a tissue-type transglutaminase (tTG). This protein belongs to a family of transglutaminases (EC 2.3.2.13) that catalyze ε-(γ-glutamyl)lysine cross-link formation between specific substrate proteins (19Folk J.E. Finlayson J.S. Adv. Protein Chem. 1977; 31: 1-133Crossref PubMed Scopus (782) Google Scholar, 20Folk J.E. Annu. Rev. Biochem. 1980; 49: 517-531Crossref PubMed Scopus (869) Google Scholar, 21Lorand L. Conrad S.M. Mol. Cell Biochem. 1984; 58: 9-35Crossref PubMed Scopus (657) Google Scholar) and are distributed widely in various tissues. The second is blood coagulation factor XIII (FXIII). This protein is also a member of the transglutaminase family and has an important role in the final stage of the blood coagulation cascade. The last is the propolypeptide of von Willebrand factor (pp-vWF). This protein is obtained from a large precursor of von Willebrand factor by specific cleavage during biosynthesis and is stored in granules of both endothelial cells and platelets (22Verweij C.L. Diergaarde P.J. Hart M. Pannekoek H. EMBO J. 1986; 5: 1839-1847Crossref PubMed Scopus (186) Google Scholar, 23Wagner D.D. Annu. Rev. Cell Biol. 1990; 6: 217-246Crossref PubMed Google Scholar). In the case of pp-vWF, we have mapped the recognition sequence for both integrins to the same cell adhesion site, a 15-residue linear sequence that we have previously shown is required for α4β1-mediated adhesion to this protein (24Isobe T. Hisaoka T. Shimizu A. Okuno M. Aimoto S. Takada Y. Saito Y. Takagi J. J. Biol. Chem. 1997; 272: 8447-8453Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar). DISCUSSIONPrevious reports identified three ligands for the integrin α9β1, VCAM-1 (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar), tenascin-C (13Yokosaki Y. Palmer E.L. Prieto A.L. Crossin K.L. Bourdon M.A. Pytela R. Sheppard D. J. Biol. Chem. 1994; 269: 26691-26696Abstract Full Text PDF PubMed Google Scholar, 14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar), and osteopontin (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar, 16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). In this report, we describe three additional ligands, tTG, FXIII, and pp-vWF. Among the previously identified α9β1 ligands, VCAM-1 and osteopontin have both been reported to be recognized by both α9β1 and the structurally related integrin α4β1 (17Bayless K.J. Meininger G.A. Scholtz J.M. Davis G.E. J. Cell Sci. 1998; 111: 1165-1174Crossref PubMed Google Scholar, 35Elices M.J. Osborn L. Takada Y. Crouse C. Luhowskyj S. Hemler M.E. Lobb R.R. Cell. 1990; 60: 577-584Abstract Full Text PDF PubMed Scopus (1508) Google Scholar). In this report, we show that each of the three new α9β1 ligands we identified is also a ligand for α4β1.Although it might seem reasonable to assume that α9β1 and α4β1recognize the same adhesive sites in shared ligands, this is not necessarily the case. There are numerous examples of different integrins recognizing distinct sites in the same ligand. For example, at least five integrins can recognize the third fibronectin type III repeat in tenascin-C as a ligand, but four of them recognize the RGD site in the F-G loop, whereas α9β1 clearly recognizes a different sequence, AEIDGIEL, in the B-C loop present on the same face of the protein (14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar). Similarly, both the integrins αvβ3 and α9β1recognize a thrombin-cleaved N-terminal fragment of osteopontin as a ligand (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar), but αvβ3 binds to an RGD site, whereas α9β1 binds to the adjacent sequence, SVVYGLR (16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). In fact, prior to the present report, there was no definitive evidence that α9β1 and α4β1 could recognize the same site in a shared ligand. The evidence presented in this report that both integrins recognize the same linear peptide, T2–15, within pp-vWF is to our knowledge the first conclusive evidence that these integrins can recognize the same cell adhesion site within one molecule (TableI). Interestingly, the sequence of this peptide, DCQDHSFSIVIETVQ, bears little resemblance to the previously identified α9β1-recognition sequences in tenascin-C and osteopontin. This observation provides additional evidence that α9β1 can recognize a surprisingly broad array of adhesive ligands. Taken together, the accumulated evidence that α9β1 and α4β1 share five ligands and, at least in one instance, recognize the same linear peptide within a ligand confirms the utility of α subunit sequence comparisons for predicting ligand binding specificity of integrin heterodimers.Table IVarious adhesion ligands that are recognized by α9β1 and/or α4β1 integrinα9β1α4β1Fibronectin×○(ILDV)VCAM-1○○(IDSP)Tenascin-C○(AEIDGIEL)?Ostcopontin○(SVVYGLR)○pp-vWF○○(DCQDHSFSIVIETVQ)tTG○○FXIII○○Adhesion to various ligands is illustrated according to the results obtained by ourselves and other investigators. ○, recognition of the integrin; ×, no recognition of the integrin; ?, no determination. The proposed essential cell adhesion sequences are shown in parentheses. Open table in a new tab The interaction between tTG and integrins is likely to be biologically significant. tTG directly binds to a number of components of the extracellular matrix, including osteopontin and tenascin-C, where it plays an important role in matrix protein cross-linking. A recent report demonstrated that tTG bound to the integrins α5β1 and αIIbβ3within the secretory apparatus prior to appearance of the integrins on the cell surface, thereby suggesting a mechanism for localization of tTG to its extracellular targets (32Akimov S, A. Krylov D. Fleischman L.F. Belkin A.M. J. Cell Biol. 2000; 148: 825-838Crossref PubMed Scopus (414) Google Scholar). Furthermore, the same study showed that the interaction of integrins with tTG enhanced cell attachment and spreading on fibronectin. The findings in the present study greatly expand the complexity of these potential interactions and suggest that similar mechanisms could be involved in cellular interactions with additional sites in fibronectin (e.g. the CS-1 site) and with a broad array of extracellular matrix ligands. Recently, as noted above, Akimov and co-workers reported that tTG could interact with several members of the integrin family, including α5β1 (as we also report in the current study), but also α1β1, α3β1, αvβ3 and αIIbβ3 (32Akimov S, A. Krylov D. Fleischman L.F. Belkin A.M. J. Cell Biol. 2000; 148: 825-838Crossref PubMed Scopus (414) Google Scholar). Interestingly, the report by Akimov et al. demonstrated that the related transglutaminase family member, FXIII, was not a ligand for α5β1, and thus suggested that the interactions between integrins and transglutaminases was specific for tTG. Although that report and this one both described interactions between α5β1 and tTG, there were several substantial differences. For example, Akimov et al. found no effect of either GRGDSP peptide or anti-β1 antibody on the interaction between tTG and integrins they describe, whereas in this report we found that GRGDSP completely eliminated the residual adhesion of G-361 cells to tTG once α9β1-mediated adhesion was inhibited, and we also found complete inhibition with anti-β1 antibody. Furthermore, we found no role for integrins other than α4β1, α5β1, or α9β1 in the adhesion of MOLT-3 or G-361 cells to tTG. We have checked the expression of various integrin subunits other than those shown in Fig. 2. As is clearly depicted in Fig. 10, G-361 cells also expressed α2, α3, α6, and αvβ3. MOLT-3 cells, however, did not express these integrins substantially. Results obtained with G-361 cells further substantiate the notion that these integrins are not involved in the adhesion of G-361 cells to tTG. There are several possible explanations for these differences. One obvious difference is that Akimov et al. were examining the effects of tTG on cell adhesion to the 42-kDa fragment of fibronectin, and in their case the tTG was supplied to integrins within the secretory apparatus of the same cell, whereas the present study examined adhesion to immobilized tTG. Under the conditions examined by Akimov et al., it is conceivable that blocking antibodies and GRGDSP peptide would not be able to displace already bound tTG, whereas these reagents were perfectly capable of binding to unligated integrin under the conditions used in the present study, thereby blocking subsequent interactions with tTG. Such an explanation is plausible because it is often more difficult to detach already adherent cells with integrin-blocking reagents than to block the attachment of suspended cells. Alternatively, the WI-38 cells and HEL cells used by Akimov et al. and the MOLT-3 cells and G-361 cells used in the present study could interact with tTG through different mechanisms.The results of the present study also clearly demonstrate that although α5β1 is not a receptor for inactive FXIII, both α4β1 and α9β1 are. These findings appear to differ from our previous report suggesting that α5β1 did contribute to adhesion of TIG-1 cells to FXIII. However, the adhesion observed in those experiments required that the FXIII be activated. The results of the present study confirm that α5β1 on G-361 cells can also mediate adhesion to activated FXIII (data not shown). We are uncertain whether the requirement for activation in this case is due to a conformational change in FXIII upon activation that unmasks an α5β1 binding site or to a requirement for enzymatic activity to induce α5β1-mediated adhesionThe interaction of α4β1 and α9β1 with FXIII could be biologically significant. Both α4β1 and α9β1 are highly expressed on specific populations of leukocytes, where they play a prominent role in transendothelial leukocyte migration. As a member of the coagulation cascade, FXIII is likely to be enriched at sites of vascular injury and inflammation, where its interaction with α4β1 and α9β1could promote leukocyte extravasation.We speculated previously about the function of pp-vWF as an emergency tag for targeting of α4β1-expressing leukocytes, together with VCAM-1, to sites of inflammation and injury (24Isobe T. Hisaoka T. Shimizu A. Okuno M. Aimoto S. Takada Y. Saito Y. Takagi J. J. Biol. Chem. 1997; 272: 8447-8453Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar). Such a mechanism would be expected to be most relevant to lymphocytes, monocytes, and eosinophils, all of which express high levels of α4β1 (36Bochner B.S. Luscinskas F.W. Gimbrone Jr., M. Newman W. Sterbinsky S.A. Derse-Anthony C.P. Klunk D. Schleimer R.P. J. Exp. Med. 1991; 173: 1553-1557Crossref PubMed Scopus (577) Google Scholar). The recent report by Taooka et al. (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar) that human neutrophils express α9β1 and utilize this integrin for migration on VCAM-1 and through activated endothelial monolayers extends this possible function to all populations of circulating leukocytes. Previous reports identified three ligands for the integrin α9β1, VCAM-1 (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar), tenascin-C (13Yokosaki Y. Palmer E.L. Prieto A.L. Crossin K.L. Bourdon M.A. Pytela R. Sheppard D. J. Biol. Chem. 1994; 269: 26691-26696Abstract Full Text PDF PubMed Google Scholar, 14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar), and osteopontin (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar, 16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). In this report, we describe three additional ligands, tTG, FXIII, and pp-vWF. Among the previously identified α9β1 ligands, VCAM-1 and osteopontin have both been reported to be recognized by both α9β1 and the structurally related integrin α4β1 (17Bayless K.J. Meininger G.A. Scholtz J.M. Davis G.E. J. Cell Sci. 1998; 111: 1165-1174Crossref PubMed Google Scholar, 35Elices M.J. Osborn L. Takada Y. Crouse C. Luhowskyj S. Hemler M.E. Lobb R.R. Cell. 1990; 60: 577-584Abstract Full Text PDF PubMed Scopus (1508) Google Scholar). In this report, we show that each of the three new α9β1 ligands we identified is also a ligand for α4β1. Although it might seem reasonable to assume that α9β1 and α4β1recognize the same adhesive sites in shared ligands, this is not necessarily the case. There are numerous examples of different integrins recognizing distinct sites in the same ligand. For example, at least five integrins can recognize the third fibronectin type III repeat in tenascin-C as a ligand, but four of them recognize the RGD site in the F-G loop, whereas α9β1 clearly recognizes a different sequence, AEIDGIEL, in the B-C loop present on the same face of the protein (14Yokosaki Y. Matsuura N. Higashiyama S. Murakami I. Obara M. Yamakido M. Shigeto N. Chen J. Sheppard D. J. Biol. Chem. 1998; 273: 11423-11428Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar). Similarly, both the integrins αvβ3 and α9β1recognize a thrombin-cleaved N-terminal fragment of osteopontin as a ligand (15Smith L.L. Cheung H.K. Ling L.E. Chen J. Sheppard D. Pytela R. Giachelli C.M. J. Biol. Chem. 1996; 271: 28485-28491Abstract Full Text Full Text PDF PubMed Scopus (231) Google Scholar), but αvβ3 binds to an RGD site, whereas α9β1 binds to the adjacent sequence, SVVYGLR (16Yokosaki Y. Matsuura N. Sasaki T. Murakami I. Schneider H. Higashiyama S. Saitoh Y. Yamakido M. Taooka Y. Sheppard D. J. Biol. Chem. 1999; 274: 36328-36334Abstract Full Text Full Text PDF PubMed Scopus (275) Google Scholar). In fact, prior to the present report, there was no definitive evidence that α9β1 and α4β1 could recognize the same site in a shared ligand. The evidence presented in this report that both integrins recognize the same linear peptide, T2–15, within pp-vWF is to our knowledge the first conclusive evidence that these integrins can recognize the same cell adhesion site within one molecule (TableI). Interestingly, the sequence of this peptide, DCQDHSFSIVIETVQ, bears little resemblance to the previously identified α9β1-recognition sequences in tenascin-C and osteopontin. This observation provides additional evidence that α9β1 can recognize a surprisingly broad array of adhesive ligands. Taken together, the accumulated evidence that α9β1 and α4β1 share five ligands and, at least in one instance, recognize the same linear peptide within a ligand confirms the utility of α subunit sequence comparisons for predicting ligand binding specificity of integrin heterodimers. Adhesion to various ligands is illustrated according to the results obtained by ourselves and other investigators. ○, recognition of the integrin; ×, no recognition of the integrin; ?, no determination. The proposed essential cell adhesion sequences are shown in parentheses. The interaction between tTG and integrins is likely to be biologically significant. tTG directly binds to a number of components of the extracellular matrix, including osteopontin and tenascin-C, where it plays an important role in matrix protein cross-linking. A recent report demonstrated that tTG bound to the integrins α5β1 and αIIbβ3within the secretory apparatus prior to appearance of the integrins on the cell surface, thereby suggesting a mechanism for localization of tTG to its extracellular targets (32Akimov S, A. Krylov D. Fleischman L.F. Belkin A.M. J. Cell Biol. 2000; 148: 825-838Crossref PubMed Scopus (414) Google Scholar). Furthermore, the same study showed that the interaction of integrins with tTG enhanced cell attachment and spreading on fibronectin. The findings in the present study greatly expand the complexity of these potential interactions and suggest that similar mechanisms could be involved in cellular interactions with additional sites in fibronectin (e.g. the CS-1 site) and with a broad array of extracellular matrix ligands. Recently, as noted above, Akimov and co-workers reported that tTG could interact with several members of the integrin family, including α5β1 (as we also report in the current study), but also α1β1, α3β1, αvβ3 and αIIbβ3 (32Akimov S, A. Krylov D. Fleischman L.F. Belkin A.M. J. Cell Biol. 2000; 148: 825-838Crossref PubMed Scopus (414) Google Scholar). Interestingly, the report by Akimov et al. demonstrated that the related transglutaminase family member, FXIII, was not a ligand for α5β1, and thus suggested that the interactions between integrins and transglutaminases was specific for tTG. Although that report and this one both described interactions between α5β1 and tTG, there were several substantial differences. For example, Akimov et al. found no effect of either GRGDSP peptide or anti-β1 antibody on the interaction between tTG and integrins they describe, whereas in this report we found that GRGDSP completely eliminated the residual adhesion of G-361 cells to tTG once α9β1-mediated adhesion was inhibited, and we also found complete inhibition with anti-β1 antibody. Furthermore, we found no role for integrins other than α4β1, α5β1, or α9β1 in the adhesion of MOLT-3 or G-361 cells to tTG. We have checked the expression of various integrin subunits other than those shown in Fig. 2. As is clearly depicted in Fig. 10, G-361 cells also expressed α2, α3, α6, and αvβ3. MOLT-3 cells, however, did not express these integrins substantially. Results obtained with G-361 cells further substantiate the notion that these integrins are not involved in the adhesion of G-361 cells to tTG. There are several possible explanations for these differences. One obvious difference is that Akimov et al. were examining the effects of tTG on cell adhesion to the 42-kDa fragment of fibronectin, and in their case the tTG was supplied to integrins within the secretory apparatus of the same cell, whereas the present study examined adhesion to immobilized tTG. Under the conditions examined by Akimov et al., it is conceivable that blocking antibodies and GRGDSP peptide would not be able to displace already bound tTG, whereas these reagents were perfectly capable of binding to unligated integrin under the conditions used in the present study, thereby blocking subsequent interactions with tTG. Such an explanation is plausible because it is often more difficult to detach already adherent cells with integrin-blocking reagents than to block the attachment of suspended cells. Alternatively, the WI-38 cells and HEL cells used by Akimov et al. and the MOLT-3 cells and G-361 cells used in the present study could interact with tTG through different mechanisms. The results of the present study also clearly demonstrate that although α5β1 is not a receptor for inactive FXIII, both α4β1 and α9β1 are. These findings appear to differ from our previous report suggesting that α5β1 did contribute to adhesion of TIG-1 cells to FXIII. However, the adhesion observed in those experiments required that the FXIII be activated. The results of the present study confirm that α5β1 on G-361 cells can also mediate adhesion to activated FXIII (data not shown). We are uncertain whether the requirement for activation in this case is due to a conformational change in FXIII upon activation that unmasks an α5β1 binding site or to a requirement for enzymatic activity to induce α5β1-mediated adhesion The interaction of α4β1 and α9β1 with FXIII could be biologically significant. Both α4β1 and α9β1 are highly expressed on specific populations of leukocytes, where they play a prominent role in transendothelial leukocyte migration. As a member of the coagulation cascade, FXIII is likely to be enriched at sites of vascular injury and inflammation, where its interaction with α4β1 and α9β1could promote leukocyte extravasation. We speculated previously about the function of pp-vWF as an emergency tag for targeting of α4β1-expressing leukocytes, together with VCAM-1, to sites of inflammation and injury (24Isobe T. Hisaoka T. Shimizu A. Okuno M. Aimoto S. Takada Y. Saito Y. Takagi J. J. Biol. Chem. 1997; 272: 8447-8453Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar). Such a mechanism would be expected to be most relevant to lymphocytes, monocytes, and eosinophils, all of which express high levels of α4β1 (36Bochner B.S. Luscinskas F.W. Gimbrone Jr., M. Newman W. Sterbinsky S.A. Derse-Anthony C.P. Klunk D. Schleimer R.P. J. Exp. Med. 1991; 173: 1553-1557Crossref PubMed Scopus (577) Google Scholar). The recent report by Taooka et al. (18Taooka Y. Chen J. Yednock T. Sheppard D. J. Cell Biol. 1999; 145: 413-420Crossref PubMed Scopus (235) Google Scholar) that human neutrophils express α9β1 and utilize this integrin for migration on VCAM-1 and through activated endothelial monolayers extends this possible function to all populations of circulating leukocytes. We thank Drs. K. Ikura, M. Hayashi, C. Morimoto, B. S. Coller, and A. Sonnenberg for valuable gifts." @default.
W2020199777 created "2016-06-24" @default.
W2020199777 creator A5001764588 @default.
W2020199777 creator A5006496734 @default.
W2020199777 creator A5016321178 @default.
W2020199777 creator A5033529548 @default.
W2020199777 creator A5043177405 @default.
W2020199777 creator A5047173299 @default.
W2020199777 creator A5079583545 @default.
W2020199777 date "2000-08-01" @default.
W2020199777 modified "2023-10-16" @default.
W2020199777 title "Tissue Transglutaminase, Coagulation Factor XIII, and the Pro-polypeptide of von Willebrand Factor Are All Ligands for the Integrins α9β1 and α4β1" @default.
W2020199777 cites W1067939983 @default.
W2020199777 cites W1552764442 @default.
W2020199777 cites W1566066927 @default.
W2020199777 cites W1607253927 @default.
W2020199777 cites W1608511206 @default.
W2020199777 cites W1679707032 @default.
W2020199777 cites W1839610592 @default.
W2020199777 cites W1973485202 @default.
W2020199777 cites W1997417732 @default.
W2020199777 cites W2013326206 @default.
W2020199777 cites W2013381560 @default.
W2020199777 cites W2014725035 @default.
W2020199777 cites W2017091343 @default.
W2020199777 cites W2019241772 @default.
W2020199777 cites W2021124377 @default.
W2020199777 cites W2029231027 @default.
W2020199777 cites W2032049587 @default.
W2020199777 cites W2034344050 @default.
W2020199777 cites W2036806537 @default.
W2020199777 cites W2050472349 @default.
W2020199777 cites W2055759016 @default.
W2020199777 cites W2062582674 @default.
W2020199777 cites W2067004325 @default.
W2020199777 cites W2072674959 @default.
W2020199777 cites W2080604344 @default.
W2020199777 cites W2086487142 @default.
W2020199777 cites W2139666587 @default.
W2020199777 cites W2166179228 @default.
W2020199777 cites W2172071407 @default.
W2020199777 cites W2175263209 @default.
W2020199777 cites W2404907151 @default.
W2020199777 cites W4211195301 @default.
W2020199777 cites W4232671899 @default.
W2020199777 cites W4249224147 @default.
W2020199777 cites W97948080 @default.
W2020199777 doi "https://doi.org/10.1074/jbc.m003526200" @default.
W2020199777 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/10816592" @default.
W2020199777 hasPublicationYear "2000" @default.
W2020199777 type Work @default.
W2020199777 sameAs 2020199777 @default.
W2020199777 citedByCount "68" @default.
W2020199777 countsByYear W20201997772012 @default.
W2020199777 countsByYear W20201997772014 @default.
W2020199777 countsByYear W20201997772015 @default.
W2020199777 countsByYear W20201997772017 @default.
W2020199777 countsByYear W20201997772018 @default.
W2020199777 countsByYear W20201997772019 @default.
W2020199777 countsByYear W20201997772021 @default.
W2020199777 countsByYear W20201997772022 @default.
W2020199777 countsByYear W20201997772023 @default.
W2020199777 crossrefType "journal-article" @default.
W2020199777 hasAuthorship W2020199777A5001764588 @default.
W2020199777 hasAuthorship W2020199777A5006496734 @default.
W2020199777 hasAuthorship W2020199777A5016321178 @default.
W2020199777 hasAuthorship W2020199777A5033529548 @default.
W2020199777 hasAuthorship W2020199777A5043177405 @default.
W2020199777 hasAuthorship W2020199777A5047173299 @default.
W2020199777 hasAuthorship W2020199777A5079583545 @default.
W2020199777 hasBestOaLocation W20201997771 @default.
W2020199777 hasConcept C126322002 @default.
W2020199777 hasConcept C170493617 @default.
W2020199777 hasConcept C178498320 @default.
W2020199777 hasConcept C181199279 @default.
W2020199777 hasConcept C185592680 @default.
W2020199777 hasConcept C186738567 @default.
W2020199777 hasConcept C195687474 @default.
W2020199777 hasConcept C203014093 @default.
W2020199777 hasConcept C2778382381 @default.
W2020199777 hasConcept C2779036427 @default.
W2020199777 hasConcept C2779394231 @default.
W2020199777 hasConcept C2779672106 @default.
W2020199777 hasConcept C2911038020 @default.
W2020199777 hasConcept C55493867 @default.
W2020199777 hasConcept C71924100 @default.
W2020199777 hasConcept C89560881 @default.
W2020199777 hasConceptScore W2020199777C126322002 @default.
W2020199777 hasConceptScore W2020199777C170493617 @default.
W2020199777 hasConceptScore W2020199777C178498320 @default.
W2020199777 hasConceptScore W2020199777C181199279 @default.
W2020199777 hasConceptScore W2020199777C185592680 @default.
W2020199777 hasConceptScore W2020199777C186738567 @default.
W2020199777 hasConceptScore W2020199777C195687474 @default.
W2020199777 hasConceptScore W2020199777C203014093 @default.
W2020199777 hasConceptScore W2020199777C2778382381 @default.
W2020199777 hasConceptScore W2020199777C2779036427 @default.
W2020199777 hasConceptScore W2020199777C2779394231 @default.