SAM domain of Arap1,2,3 (angiotensin receptor-associated protein)
SAM (sterile alpha motif) domain of Arap1,2,3 subfamily proteins (angiotensin receptor-associated) is a protein-protein interaction domain. Arap1,2,3 proteins are phosphatidylinositol-3,4,5-trisphosphate-dependent GTPase-activating proteins. They are involved in phosphatidylinositol-3 kinase (PI3K) signaling pathways. In addition to SAM domain, Arap1,2,3 proteins contain ArfGap, PH-like, RhoGAP and UBQ domains. SAM domain of Arap3 protein was shown to interact with SAM domain of Ship2 phosphatidylinositol-trisphosphate phosphatase proteins. Such interaction apparently plays a role in inhibition of PI3K regulated pathways since Ship2 converts PI(3,4,5)P3 into PI(3,4)P2. Proteins of this subfamily participate in regulation of signaling and trafficking associated with a number of different receptors (including EGFR, TRAIL-R1/DR4, TRAIL-R2/DR5) in normal and cancer cells; they are involved in regulation of actin cytoskeleton remodeling, cell spreading and formation of lamellipodia.
Comment:Highlighted residues are important for SAM_Arap3/SAM_Ship2 heterodimer formation via the end-helix (EH) surface of SAM_Arap3 (based on chemical shift perturbation, isothermal titration calorimetry, mutagenesis and molecular modeling analysis).
Jiyao W et al.(2023). "The conserved domain database in 2023.",