SAM domain of EPH-A2 family of tyrosine kinase receptors
SAM (sterile alpha motif) domain of EPH-A2 subfamily of receptor tyrosine kinases is a C-terminal protein-protein interaction domain. This domain is located in the cytoplasmic region of EPH-A2 receptors and appears to mediate cell-cell initiated signal transduction. For example, SAM domain of EPH-A2 receptors interacts with SAM domain of Ship2 proteins (SH2 containing phosphoinositide 5-phosphotase-2) forming heterodimers; such recruitment of Ship2 by EPH-A2 attenuates the positive signal for receptor endocytosis. Eph-A2 is found overexpressed in many types of human cancer, including breast, prostate, lung and colon cancer. High level of expression could induce cancer progression by a variety of mechanisms and could be used as a novel tag for cancer immunotherapy. EPH-A2 receptors are attractive targets for drag design.
Comment:None of the three tyrosine residues belonging to SAM was identified as phosphorylated, based on mass spectrometry and phosphopeptide mapping analysis.