RAB3GAP1:RAB3GAP2 exchanges GTP for GDP on RAB18

Stable Identifier
Reaction [transition]
Homo sapiens
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RAB18 is a highly conserved RAB GTPase with roles in Golgi to ER trafficking, lipid droplet formation and the regulation of secretory granules and peroxisomes (Dejgaard et al, 2008; Gerondopoulos et al, 2014; Martin et al, 2005; Ozeki et al, 2005; Vazquez-Martinez et al, 2007; Gronemeyer et al, 2013). RAB18 is recruited to the ER membrane by the RAB18 GEF complex RAB3GAP1:RAB3GAP2, a complex that was initially identified and characterized for its GAP activity towards RAB3 (Gerondopoulos et al, 2013; Fukui et al, 1997; Nagano et al, 1998; reviewed in Ishida et al, 2016). Interaction of RAB18:GDP with its GEF promotes release of GDP, allowing GTP to bind, and precludes the interaction of RAB18 with GDI and CHM proteins. Mutations in RAB18, RAB3GAP1 or RAB3GAP2 are associated with Warburg Micro syndromes, characterized by ocular and neurological abnormalities (Handley and Aligianis, 2013; reviewed in Handley and Aligianis, 2012).

Literature References
PubMed ID Title Journal Year
15914536 Rab18 localizes to lipid droplets and induces their close apposition to the endoplasmic reticulum-derived membrane

Ozeki, S, Tauchi-Sato, K, Cheng, J, Hatano, N, Fujimoto, T, Taniguchi, H

J. Cell. Sci. 2005
24891604 Rab18 and a Rab18 GEF complex are required for normal ER structure

Aligianis, I, Handley, MT, Barr, FA, Gerondopoulos, A, Yoshimura, S, Bastos, RN, Anderson, R, Carpanini, S

J. Cell Biol. 2014
18664496 Rab18 and Rab43 have key roles in ER-Golgi trafficking

Presley, JF, Verbich, D, Lodge, R, Murshid, A, Dejgaard, K, Kizilay, O, Simpson, JC, Pepperkok, R, Ly-Hartig, TB, Dejgaard, SY, Erman, A

J. Cell. Sci. 2008
16207721 Regulated localization of Rab18 to lipid droplets: effects of lipolytic stimulation and inhibition of lipid droplet catabolism

Martin, S, Parton, RG, Nixon, SJ, Driessen, K, Zerial, M

J. Biol. Chem. 2005
23333653 Localization of Rab proteins to peroxisomes: a proteomics and immunofluorescence study

Schollenberger, L, Wiese, S, Gronemeyer, T, Grinhagens, S, Meyer, HE, Satyagraha, A, Just, WW, Warscheid, B, Huber, LA

FEBS Lett. 2013
17488286 Rab18 inhibits secretory activity in neuroendocrine cells by interacting with secretory granules

Vazquez-Martinez, R, Cruz-Garcia, D, CastaƱo, JP, Peinado, JR, Malagon, MM, Duran-Prado, M

Traffic 2007
23176487 RAB3GAP1, RAB3GAP2 and RAB18: disease genes in Micro and Martsolf syndromes

Handley, MT, Aligianis, IA

Biochem. Soc. Trans. 2012
9733780 Molecular cloning and characterization of the noncatalytic subunit of the Rab3 subfamily-specific GTPase-activating protein

Takai, Y, Fukui, K, Asakura, T, Nagano, F, Sasaki, T, Imazumi, K

J. Biol. Chem. 1998
9030515 Isolation and characterization of a GTPase activating protein specific for the Rab3 subfamily of small G proteins

Nakanishi, H, Takai, Y, Fukui, K, Matsuura, Y, Sasaki, T, Imazumi, K

J. Biol. Chem. 1997
23420520 Mutation spectrum in RAB3GAP1, RAB3GAP2, and RAB18 and genotype-phenotype correlations in warburg micro syndrome and Martsolf syndrome

Zaki, MS, Borck, G, Stewart, H, Martorell, L, Lederer, D, Macdonald, F, Jackson, IJ, Mowat, D, Edery, P, Pinelli, L, Carpanini, SM, Glass, I, Plomp, AS, Abdel-Salam, GM, Maher, ER, Mancini, G, Faravelli, F, Rolfs, A, Izzi, C, Graham, JM, Handley, MT, Garcia-Cazorla, A, Poo, P, Basel-Vanagaite, L, Hardy, C, Accorsi, P, Aligianis, IA, Jansen, A, Seemanova, E, Giuliano, F, Peretz, G, Bem, D, Morris-Rosendahl, DJ, Roscioli, T, Brown, S

Hum. Mutat. 2013
Catalyst Activity

guanyl-nucleotide exchange factor activity of RAB3GAP1:RAB3GAP2 [cytosol]

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