cd05114: PTKc_Tec_Rlk (this model, PSSM-Id:173658 is obsolete and has been replaced by 270685)
Catalytic domain of the Protein Tyrosine Kinases, Tyrosine kinase expressed in hepatocellular carcinoma and Resting lymphocyte kinase
Protein Tyrosine Kinase (PTK) family; Tyrosine kinase expressed in hepatocellular carcinoma (Tec) and Resting lymphocyte kinase (Rlk); 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. Tec and Rlk (also named Txk) are members of the Tec subfamily of proteins, which are cytoplasmic (or nonreceptor) tyr kinases with similarity to Src kinases in that they contain Src homology protein interaction domains (SH3, SH2) N-terminal to the catalytic tyr kinase domain. Unlike Src kinases, most Tec subfamily members (except Rlk) also contain an N-terminal pleckstrin homology (PH) domain, which binds the products of PI3K and allows membrane recruitment and activation. Instead of PH, Rlk contains an N-terminal cysteine-rich region. In addition to PH, Tec also contains the Tec homology (TH) domain with proline-rich and zinc-binding regions. Tec kinases are expressed mainly by haematopoietic cells. Tec is more widely-expressed than other Tec subfamily kinases. It is found in endothelial cells, both B- and T-cells, and a variety of myeloid cells including mast cells, erythroid cells, platelets, macrophages and neutrophils. Rlk is expressed in T-cells and mast cell lines. Tec and Rlk are both key components of T-cell receptor (TCR) signaling. They are important in TCR-stimulated proliferation, IL-2 production and phopholipase C-gamma1 activation.
Comment:Based on the structures of other PTK family members bound to substrate peptides and ATP analogs as well as, the structure of human Itk bound with staurosporine inhibitor at the ATP binding site (1SM2_A).