The following text describes a protein:
Function:
Guanine nucleotide exchange factor (GEF) which activates RAB21 and possibly RAB28 (By similarity). Promotes the exchange of GDP to GTP, converting inactive GDP-bound Rab proteins into their active GTP-bound form (By similarity). In response to starvation-induced autophagy, activates RAB21 which in turn binds to and regulates SNARE protein VAMP8 endolysosomal transport required for SNARE-mediated autophagosome-lysosome fusion (By similarity). Acts as an adapter for the phosphatase MTMR2. Increases MTMR2 catalytic activity towards phosphatidylinositol 3,5-bisphosphate and to a lesser extent towards phosphatidylinositol 3-phosphate.
Subcellular Localization:
Cytoplasm. Cytoplasm, perinuclear region. Membrane; Peripheral membrane protein. Endosome membrane; Peripheral membrane protein. Cell projection, axon. Note=Associated with membranes (By similarity). Localizes to vacuoles in hypo-osmotic conditions. Membrane localization is likely to be mediated via its interaction with MTMR2.
Domain:
The C-terminal domain mediates homodimerization. By mediating SBF2/MTMR13 homodimerization, indirectly involved in SBF2/MTMR13 and MTMR2 homotetramerization; The GRAM domain mediates binding to phosphatidylinositol 4-phosphate, phosphatidylinositol 5-phosphate, phosphatidylinositol 3,5-biphosphate and phosphatidylinositol 3,4,5-trisphosphate; The PH domain binds preferentially phosphatidylinositol 3,4,5-trisphosphate. Appears to be dispensable for localization to membranes.
Sequence:
MARLADYFIVVGYDHEKPAGPGEGLGKIIQRFPQQDWDDTPFPQGIELFCQPGGWHLSRERKQPTFFVVVLTDIDSDRHYCSCLTFYEAEINLQGTKKEEIEGEEVSGLIQPAEVFAPKSLVLVSRLDYPEIFRACLGLIYTVYVDSMSVSLESLIANLCACLVPAAGGSQKLFSLGAGDRQLIQTPLHDSLPVTGTSVALLFQQLGIQNVLNLFCAVLTENKVLFHSASFQRLSDACRALESLMFPLKYSYPYIPILPAQLLEVLSSPTPFIIGVHSIFKTDVHELLDVIIADLDGGTIKIPECIHLSSLPEPLLHQTQSALSLILHPDLEVADHAFPPPRTALSHSKMLDKEVRAVFLRLFAQLFQGYRSCLQLIRIHAEPVIHFHKTAFLGQRGLVENDFLTKVLNGMAFAGFVSERGPPYRACDLFDELVAFEVERIKVEEKNPLKMIKHIRELAEQLFKNENPNPHMAFQKVPRPTEGSHLRVHILPFPKINEARVQELIQENLAKNQNAPPATRIEKKCVVPAGPPVVSIMEKVITVFNSAQRLEVVRNCISFIFENKTLETEKTLPAALRALKGKAARQCLTDELGLHVQQNRAILDHQQFDYIIRMMNCTLQDCSSLEEYNIAAALLPLTSAFYRKLAPGVSQFAYTCVQDHPIWTNQQFWETTFYNAVQEQVRSLYLSAKDDNHIPHLKQKLPDGQHQEKTAMDLAAEQLRLWPTLSKSTQQELVQHEESTVFSQAIHFANLMVNLLVPLDTSKNKLLRASAPGDWESGSNSIVTNSIAGSVAESYDTESGFEDSENSDVANSVVRFIARFIDKVCTESGVTQDHIRSLHCMIPGIVAMHIETLEAVHRESRRLPPIQKPKILRPALLPGEEIVCEGLRVLLDPDGREEATGGLLGGPQLLPAEGALFLTTYRILFRGTPHDQLVGEQTVVRSFPIASITKEKKITMQNQLQQSVQEGLQITSASFQLIKVAFDEEVSPEVVDIFKKQLMKFRYPQSIFSTFAFAAGQTTPQIILPKQKEKNTSFRTFSKTIVKGAKKAGKMTIGRQYLLKKRTGTIVEERVNRPGWNEEDDISVSDDSELPTSTTLKASEKSTMEQLVEKACFRDYQRLGLGTISGNSSRSKPEYFRVTASNRLYSLCRSYPGLLVIPQAVQDSSLPRVARCYRHNRLPVVCWKNSRSGTLLLRSGGFHGKGVVGLFKSQNSPQAVSTSSLESSSSIEQEKYLQALLTAVIVHQKLRGSSTLTVRPALALSPVHGYRDKSFTQSNPKSSAKEPVHNQGVWASLRSSTRLISSPTSFIDVGARLAGKDHSASFSNSTYLQNQLLKRQAALYIFGEKSQLRSSKVEFAFNCEFVPVEFHEIRQVKASFKKLMRACIPSTIPTDSEVTFLKALGDSEWFPQLHRIMQLAVVVSEVLENGSSVWVCLEEGWDITTQVTSLAQLLSDPFYRTIAGFRTLVEKEWLSFGHKFSQRSSLALNSQGGGFAPIFLQFLDCVHQVHNQYPTEFEFNLYYLKFLAFHYVSNRFKTFLLDSDYERLEHGTLFDDKGDKHAKKGVCIWECIDKMHTRSPIFFNYLYSPVEVEALKPNVNVSSLKKWDYYTEETLSAGPSYDWMMLTPKHFPYEESDVAGGAGPQSQRKTVWPCYDDVTCSQPDALTRLFSEIEKLEHKLNQTPERWHQLWEKVTTDLKEEPRTAHSLRHSAGSPGIASTNVPSYQKRPALHPLHRGLGEDQSTTTAPSNGVEHRAATLYSQYTSKNDENRSFEGTLYKRGALLKGWKPRWFVLDVTKHQLRYYDSGEDTSCKGHIDLAEVEMVIPAGPSMGAPKYTSDKAFFDLKTSKRVYNFCAQDGQSAQQWMDRIQSCISDA