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- W2262062160 abstract "Receptor kinases possessing intrinsic guanylate cyclase (GC) activity constitute a family of catalytically active membrane-bound proteins that play crucial roles in a myriad of signal transduction processes. Currently known GC-linked receptor kinases have an extracellular ligand-binding domain and an intracellular portion that is composed of an inactive kinase homology domain and a functional GC catalytic centre. A novel class of GC-linked receptor kinases was unearthed using homology-guided bioinformatic data mining tools designed from annotated amino acid residues in the GC catalytic centres of lower eukaryotes. The GC catalytic centre in this new class of receptor kinases is encapsulated within an active kinase domain, thereby conferring a dual catalytic function to this class of proteins. This is contrary to currently known classical GC-linked receptor kinases, which are mono-functional. There are currently four members of this novel class of receptor kinases which have been demonstrated to possess intrinsic GC and kinase activity. However, there is a paucity of information as to how this dual catalysis is physiologically regulated. In an attempt to uncover the modulatory mechanisms regulating the dual catalysis of novel GC-linked receptor kinases, this thesis examines the elements influencing the dual catalysis of the phytosulfokine receptor, PSKR1. Most specifically, this study focuses on how receptor dimerisation, phosphorylation, and the effect of intracellular signalling molecules like calcium and ATP influence PSKR1’s intrinsic dual catalysis. Analytical ultracentrifugation and size exclusion chromatography have demonstrated that the recombinantly expressed cytoplasmic domain of PSKR1 is reversibly dimeric in solution. This observation probably represents a catalytically competent physiological arrangement of the receptor that may be a pre-requisite for PSKR1-mediated nucleotide cyclase and phospho-transferase activity.Mapping out of the phosphorylation pattern in the cytoplasmic domain of PSKR1 using tandem mass spectroscopy identified 14 phosphorylation sites; eight phosphoserines, three phosphothreonines and three phosphotyrosines. Further in vitro studies revealed that PSKR1 is capable of self-phosphorylating and that phosphorylation is essential for PSKR1-mediated dual catalysis. Apart from its obvious role in phosphorylation, ATP seemed to potentiate the nucleotide cyclase activity of PSKR1, possibly through allosteric modulation. Intriguingly, calcium had a direct influence in regulating PSKR1-mediated dual catalysis without the aid of calcium sensor proteins such as calmodulin. At physiologically high calcium concentrations, PSKR1’s nucleotide cyclase activity was enhanced while on the other hand the phospho-transferase activity of PSKR1 was significantly suppressed. This observation points to calcium acting as a molecular switch regulating the dual catalysis of PSKR1.Taken together, the findings obtained in this study informs a proposed model of how all these regulatory elements modulate PSKR1-mediated dual catalysis. In summation, the presence of catalytically relevant motifs within functional protein domains allows signalling proteins to self-regulate and fine-tune their signal output in concert with their immediate cellular environment. This necessitates the need for prospective studies to carry out similar bioinformatics search strategies in order to uncover hidden regulatory elements that facilitate the self-regulation of proteins." @default.
- W2262062160 created "2016-06-24" @default.
- W2262062160 creator A5025168440 @default.
- W2262062160 date "2015-01-01" @default.
- W2262062160 modified "2023-09-27" @default.
- W2262062160 title "Mechanistic modulation of a bifunctional GC-linked receptor kinase, PSKR1" @default.
- W2262062160 cites W1486995987 @default.
- W2262062160 cites W1524181357 @default.
- W2262062160 cites W1543394229 @default.
- W2262062160 cites W1552901871 @default.
- W2262062160 cites W1565017492 @default.
- W2262062160 cites W1566175888 @default.
- W2262062160 cites W1573211116 @default.
- W2262062160 cites W1601387977 @default.
- W2262062160 cites W1607672162 @default.
- W2262062160 cites W1646036135 @default.
- W2262062160 cites W1808207588 @default.
- W2262062160 cites W1843499184 @default.
- W2262062160 cites W1875580551 @default.
- W2262062160 cites W1933063923 @default.
- W2262062160 cites W1964066576 @default.
- W2262062160 cites W1967456341 @default.
- W2262062160 cites W1967931222 @default.
- W2262062160 cites W1968573434 @default.
- W2262062160 cites W1968692119 @default.
- W2262062160 cites W1971247049 @default.
- W2262062160 cites W1972616722 @default.
- W2262062160 cites W1972809836 @default.
- W2262062160 cites W1973034955 @default.
- W2262062160 cites W1976032358 @default.
- W2262062160 cites W1977573465 @default.
- W2262062160 cites W1978179863 @default.
- W2262062160 cites W1978497485 @default.
- W2262062160 cites W1978781920 @default.
- W2262062160 cites W1982903698 @default.
- W2262062160 cites W1984474897 @default.
- W2262062160 cites W1984950210 @default.
- W2262062160 cites W1985501533 @default.
- W2262062160 cites W1990075625 @default.
- W2262062160 cites W1990494960 @default.
- W2262062160 cites W1994207647 @default.
- W2262062160 cites W1994377900 @default.
- W2262062160 cites W1995666296 @default.
- W2262062160 cites W1996085478 @default.
- W2262062160 cites W1996199957 @default.
- W2262062160 cites W1998465616 @default.
- W2262062160 cites W2000350495 @default.
- W2262062160 cites W2000390423 @default.
- W2262062160 cites W2001435676 @default.
- W2262062160 cites W2002585058 @default.
- W2262062160 cites W2004811338 @default.
- W2262062160 cites W2007725161 @default.
- W2262062160 cites W2008276294 @default.
- W2262062160 cites W2009335569 @default.
- W2262062160 cites W2010694921 @default.
- W2262062160 cites W2012847956 @default.
- W2262062160 cites W2015714994 @default.
- W2262062160 cites W2015852603 @default.
- W2262062160 cites W2016962299 @default.
- W2262062160 cites W2017163862 @default.
- W2262062160 cites W2017697139 @default.
- W2262062160 cites W2017980572 @default.
- W2262062160 cites W2019190661 @default.
- W2262062160 cites W2019974917 @default.
- W2262062160 cites W2020257412 @default.
- W2262062160 cites W2020459598 @default.
- W2262062160 cites W2022314126 @default.
- W2262062160 cites W2024443524 @default.
- W2262062160 cites W2025172590 @default.
- W2262062160 cites W2026233197 @default.
- W2262062160 cites W2026949048 @default.
- W2262062160 cites W2027326530 @default.
- W2262062160 cites W2028886223 @default.
- W2262062160 cites W2029929326 @default.
- W2262062160 cites W2030039340 @default.
- W2262062160 cites W2032684296 @default.
- W2262062160 cites W2034840549 @default.
- W2262062160 cites W2036478036 @default.
- W2262062160 cites W2036956062 @default.
- W2262062160 cites W2039399096 @default.
- W2262062160 cites W2043571529 @default.
- W2262062160 cites W2045016821 @default.
- W2262062160 cites W2049079227 @default.
- W2262062160 cites W2049120699 @default.
- W2262062160 cites W2049947111 @default.
- W2262062160 cites W2050274628 @default.
- W2262062160 cites W2050778135 @default.
- W2262062160 cites W2052673513 @default.
- W2262062160 cites W2053561335 @default.
- W2262062160 cites W2055149392 @default.
- W2262062160 cites W2057029647 @default.
- W2262062160 cites W2057069307 @default.
- W2262062160 cites W2057358596 @default.
- W2262062160 cites W2062257377 @default.
- W2262062160 cites W2062801286 @default.
- W2262062160 cites W2064072535 @default.
- W2262062160 cites W2064483138 @default.
- W2262062160 cites W2065462380 @default.
- W2262062160 cites W2068101913 @default.
- W2262062160 cites W2068660161 @default.