RNA recognition motif (RRM) found in synaptojanin-2 and similar proteins
This subgroup corresponds to the RRM of synaptojanin-2, also termed synaptic inositol-1,4,5-trisphosphate 5-phosphatase 2, an ubiquitously expressed central regulatory enzyme in the phosphoinositide-signaling cascade. As a novel Rac1 effector regulating the early step of clathrin-mediated endocytosis, synaptojanin-2 acts as a polyphosphoinositide phosphatase directly and specifically interacting with Rac1 in a GTP-dependent manner. It mediates the inhibitory effect of Rac1 on endocytosis and plays an important role in the Rac1-mediated control of cell growth. Synaptojanin-2 shows high sequence homology to the N-terminal Sac1p homology domain, the central inositol 5-phosphatase domain, the putative RNA recognition motif (RRM) of synaptojanin-1, but differs in the proline-rich region.