cd05070: PTKc_Fyn_Yrk (this model, PSSM-Id:133201 is obsolete and has been replaced by 270655)
Catalytic domain of the Protein Tyrosine Kinases, Fyn and Yrk
Protein Tyrosine Kinase (PTK) family; Fyn and Yrk kinases; catalytic (c) domain. The PTKc family is part of a larger superfamily that includes the catalytic domains of other kinases such as protein serine/threonine kinases, RIO kinases, and phosphoinositide 3-kinase (PI3K). PTKs catalyze the transfer of the gamma-phosphoryl group from ATP to tyrosine (tyr) residues in protein substrates. Fyn and Yrk are members of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) tyr kinases. Src kinases contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). Src proteins are involved in signaling pathways that regulate cytokine and growth factor responses, cytoskeleton dynamics, cell proliferation, survival, and differentiation. Fyn, together with Lck, plays a critical role in T-cell signal transduction by phosphorylating ITAM (immunoreceptor tyr activation motif) sequences on T-cell receptors, ultimately leading to the proliferation and differentiation of T-cells. In addition, Fyn is involved in the myelination of neurons, and is implicated in Alzheimer's and Parkinson's diseases. Yrk has been detected only in chickens. It is primarily found in neuronal and epithelial cells and in macrophages. It may play a role in inflammation and in response to injury.
Comment:Based on the structures of other PTK family members bound to substrate peptides and ATP analogs as well as, the structure of human Fyn tyr kinase bound with the inhibitor, staurosporine (2DQ7_X).