cd05075: PTKc_Axl (this model, PSSM-Id:173642 is obsolete and has been replaced by 270660)
Catalytic domain of the Protein Tyrosine Kinase, Axl
Protein Tyrosine Kinase (PTK) family; Axl; 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. Axl is a member of the Axl subfamily, which is composed of receptor tyr kinases (RTKs) containing an extracellular ligand-binding region with two immunoglobulin-like domains followed by two fibronectin type III repeats, a transmembrane segment, and an intracellular catalytic domain. Binding to their ligands, Gas6 and protein S, leads to receptor dimerization, autophosphorylation, activation, and intracellular signaling. Axl is widely expressed in a variety of organs and cells including epithelial, mesenchymal, hematopoietic, as well as non-transformed cells. Axl signaling is important in many cellular functions such as survival, anti-apoptosis, proliferation, migration, and adhesion. Axl was originally isolated from patients with chronic myelogenous leukemia and a chronic myeloproliferative disorder. Axl is overexpressed in many human cancers including colon, squamous cell, thyroid, breast, and lung carcinomas.