C-terminal SARAH domain found in Ras-association domain-containing protein 6 (RASSF6)
RASSF6 is one of six related proteins, the classical RASSF proteins (RASSF1-6), that contain a conserved RalGDS/AF6 Ras association (RA) domain located towards the C-terminus. It acts as a tumor suppressor protein involved in the induction of apoptosis, through both caspase-dependent and caspase-independent pathways. RASSF6 may function as a Ras effector protein. It is ubiquitinated and degraded by interacting with MDM2 to stabilize P53, and it regulates apoptosis and the cell cycle. RASSF6 is expressed as four transcripts via alternative splicing. All transcript variants of RASSF6 contain the RA and SARAH (Salvador-RassF-Hippo) domains. The RA domain of the classical RASSF proteins has the beta-grasp ubiquitin-like fold with low sequence similarity to ubiquitin. RA domains mediate interactions with Ras and other small GTPases. SARAH domains mediate protein-protein interactions crucial in the pathways that induce cell cycle arrest and apoptosis. This model corresponds to the SARAH domain of RASSF6.