MmuEX6099595 @ mm9

All four RBEL1 isoforms (A, B, C, and D) have identical N termini harboring the Rab-like GTPase domains but contain variable C termini. Although all isoforms can be detected in both cytoplasm and nucleus, RBEL1A is predominantly cytoplasmic, whereas RBEL1B is mostly nuclear. RBEL1C and -D, by contrast, are evenly distributed between the cytoplasm and nucleus. Furthermore, all four RBEL1 proteins are also capable of associating with cellular membrane. The RBEL1 proteins also exhibit a unique nucleotide-binding potential and, whereas the larger A and B isoforms are mainly GTP-bound, the smaller C and D variants bind to both GTP and GDP. Furthermore, a regulatory region at amino acid position 236-302 immediately adjacent to the GTP-binding domain is important for GTP-binding potential of RBEL1A, because deletion of this region converts RBEL1A from predominantly GTP-bound to GDP-bound. RBEL1 knockdown via RNA interference results in marked cell growth suppression, which is associated with morphological and biochemical features of apoptosis as well as inhibition of extracellular signal-regulated kinase phosphorylation. Notes: C and D: internal APA, the difference is HsaINT0025589 (retained in D). B: ALTD (ex 9, HsaALTD0001096) top ALTA (ex 15, not in VastDB) skipping exons 10 (not in VastDB), 11 (HsaEX1030457), 12 (HsaEX7005708), 13 (HsaEX6064086), 14 (HsaEX6064085).