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• W268630872 abstract "Mycobacterium tuberculosis (Mtb) coordinates a wide variety of metabolic and cellular responses to changing external environments throughout the multiple stages of infection. Signaling kinases are critical for these responses. The Mtb genome encodes 11 Serine/Threonine Protein Kinases (STPKs) that function as important nodes of this sensing and response network, but the chemical and structural changes that mediate kinase activation have not been elucidated. Autophosphorylation activates several of the Mtb STPKs, and kinase dimerization can activate receptor kinases for autophosphorylation through an allosteric dimer interface. Inter-kinase phosphorylation has been reported, but the function and specificity of these interactions remain unknown. In this study, a biochemical approach was used to comprehensively map the cross-kinase trans-phosphorylation activity of the Mtb STPKs. The results reveal a pattern of kinase interactions that suggests each protein plays a distinct regulatory role in controlling cellular processes by phosphorylating other kinases. The PknB and PknH STPKs act in vitro as master regulators that are activated only through autophosphorylation and also phosphorylate other STPKs. In contrast, the signal-transduction kinases PknE, PknJ and PknL are phosphorylated by the master regulatory STPKs and phosphorylate other kinases. The substrate STPKs PknA, PknD, PknF and PknK are phosphorylated by upstream STPKs, but do not phosphorylate other kinases. The delineation of the Mtb STPK signaling networks reveals for the first time the specific network of STPK phosphorylation that may mediate the intracellular signaling circuitry. STPKS are activated and inhibited by phosphorylation at different residues. The regulatory role of the extensive Mtb STPK trans-phosphorylation network is unknown. Through mass spectrophotometry and mutagenesis, the amino acids targeted by each phosphorylation were identified. I find that key activation loop residues are the targets of both autophosphorylation and trans-phosphorylation. Mutation of the two conserved threonines in the activation loops of nine Mtb STPKs renders the kinases inactive. These results demonstrate that activation loop phosphorylation is a common mechanism of Mtb STPK activation. To explore the structural implications of activation loop phosphorylation, I determined the crystal structures of the phosphorylated and unphosphorylated Mtb PknH kinase domain. The PknH kinase domain forms a back-to-back dimer observed previously in the structures of Mtb PknB and PknE. Amino-acid substitutions in the dimer interface fail to block kinase dimerization or autophosphorylation. Unexpectedly, the PknH activation loop is folded in the unphosphorylated form and disordered in the active, phosphorylated enzyme. These structures revealed that the back-to-back kinase dimer is a surprisingly stable structure that does not undergo global conformational changes with phosphorylation or nucleotide binding. Unlike the well-established, conformational regulatory mechanisms of eukaryotic STPKs, PknH activation may be a biochemical process mediated by changes in nucleotide affinity or activation loop disorder rather than remodeling of the overall kinase-domain architecture. To establish the effects of stepwise phosphorylation of an Mtb STPK, I determined the structures of the PknK kinase domain modified with 0, 1, or multiple phosphoryl groups. PknK is one of the two solution STPKs in Mtb and is phosphorylated by multiple upstream kinases. Mass spectrophotometry revealed that the trans-phosphorylation and autophosphorylation reactions resulted in varying numbers of phosphate groups on this substrate protein. Crystal structures revealed that, like PknH, PknK does not undergo conformational remodeling following activation loop phosphorylation. Unlike many eukaryotic homologs, the unphosphorylated forms of PknH and PknK bind ATP analogs. These two examples suggest that phosphorylation activates the Mtb STPKs by directly changing the properties of the activation loop. Based on these results, I propose the testable new idea that activation loop phosphorylation may regulate the Mtb STPKs by directly changing the affinities for protein substrates or nucleotides. The absence of conformational remodeling of PknH and PknK upon activation loop phosphorylation implies that the prokaryotic and eukaryotic STPKs are regulated by different mechanisms." @default.
• W268630872 created "2016-06-24" @default.
• W268630872 creator A5062673144 @default.
• W268630872 date "2010-01-01" @default.
• W268630872 modified "2023-09-24" @default.
• W268630872 title "Mechanisms of Mycobacterium tuberculosis Serine/Threonine Protein Kinase Activation" @default.
• W268630872 cites W1490764204 @default.
• W268630872 cites W1495926848 @default.
• W268630872 cites W1810897610 @default.
• W268630872 cites W1875580551 @default.
• W268630872 cites W1970600676 @default.
• W268630872 cites W1972674299 @default.
• W268630872 cites W1972893231 @default.
• W268630872 cites W1974160984 @default.
• W268630872 cites W1978137652 @default.
• W268630872 cites W1990650937 @default.
• W268630872 cites W1992055692 @default.
• W268630872 cites W1992945955 @default.
• W268630872 cites W1996038152 @default.
• W268630872 cites W1997601530 @default.
• W268630872 cites W2003229373 @default.
• W268630872 cites W2008595027 @default.
• W268630872 cites W2009943501 @default.
• W268630872 cites W2014309889 @default.
• W268630872 cites W2016021369 @default.
• W268630872 cites W2017369100 @default.
• W268630872 cites W2019249774 @default.
• W268630872 cites W2020764576 @default.
• W268630872 cites W2025789697 @default.
• W268630872 cites W2030205108 @default.
• W268630872 cites W2030554179 @default.
• W268630872 cites W2034195376 @default.
• W268630872 cites W2035887815 @default.
• W268630872 cites W2039345443 @default.
• W268630872 cites W2039375835 @default.
• W268630872 cites W2040077679 @default.
• W268630872 cites W2040594219 @default.
• W268630872 cites W2043519753 @default.
• W268630872 cites W2048411595 @default.
• W268630872 cites W2049277771 @default.
• W268630872 cites W2050103345 @default.
• W268630872 cites W2051225819 @default.
• W268630872 cites W2052420692 @default.
• W268630872 cites W2052448152 @default.
• W268630872 cites W2055791119 @default.
• W268630872 cites W2058034454 @default.
• W268630872 cites W2058558815 @default.
• W268630872 cites W2059907843 @default.
• W268630872 cites W2060259273 @default.
• W268630872 cites W2060527882 @default.
• W268630872 cites W2060810338 @default.
• W268630872 cites W2062315420 @default.
• W268630872 cites W2062471223 @default.
• W268630872 cites W2063780770 @default.
• W268630872 cites W2064910808 @default.
• W268630872 cites W2072256609 @default.
• W268630872 cites W2072737923 @default.
• W268630872 cites W2075929473 @default.
• W268630872 cites W2077512363 @default.
• W268630872 cites W2080568049 @default.
• W268630872 cites W2081833742 @default.
• W268630872 cites W2084517238 @default.
• W268630872 cites W2085010866 @default.
• W268630872 cites W2086987219 @default.
• W268630872 cites W2089574530 @default.
• W268630872 cites W2095724872 @default.
• W268630872 cites W2096221200 @default.
• W268630872 cites W2102058219 @default.
• W268630872 cites W2106246537 @default.
• W268630872 cites W2108296383 @default.
• W268630872 cites W2108804414 @default.
• W268630872 cites W2109606373 @default.
• W268630872 cites W2110695538 @default.
• W268630872 cites W2113189019 @default.
• W268630872 cites W2118460316 @default.
• W268630872 cites W2119838034 @default.
• W268630872 cites W2124026197 @default.
• W268630872 cites W2127041573 @default.
• W268630872 cites W2127469284 @default.
• W268630872 cites W2132473872 @default.
• W268630872 cites W2132629607 @default.
• W268630872 cites W2133942178 @default.
• W268630872 cites W2134570357 @default.
• W268630872 cites W2140816363 @default.
• W268630872 cites W2142380475 @default.
• W268630872 cites W2142964541 @default.
• W268630872 cites W2143724068 @default.
• W268630872 cites W2147049072 @default.
• W268630872 cites W2148205722 @default.
• W268630872 cites W2150588192 @default.
• W268630872 cites W2154714625 @default.
• W268630872 cites W2156480395 @default.
• W268630872 cites W2157099767 @default.
• W268630872 cites W2160483498 @default.
• W268630872 cites W2163341755 @default.
• W268630872 cites W2163407348 @default.
• W268630872 cites W2164367233 @default.
• W268630872 cites W2165710306 @default.
• W268630872 cites W2166834087 @default.
• W268630872 cites W2169802422 @default.

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