RAB1B

Members of the RAB protein family, such as RAB1B, are low molecular mass monomeric GTPases localized on the cytoplasmic surfaces of distinct membrane-bound organelles. RAB1B functions in the early secretory pathway and is essential for vesicle transport between the endoplasmic reticulum (ER) and Golgi (Chen et al., 1997 [PubMed 9030196]; Alvarez et al., 2003 [PubMed 12802079]).[supplied by OMIM

Full Name

RAB1B, member RAS oncogene family

Function

The small GTPases Rab are key regulators of intracellular membrane trafficking, from the formation of transport vesicles to their fusion with membranes (PubMed:20545908, PubMed:9437002).
Rabs cycle between an inactive GDP-bound form and an active GTP-bound form that is able to recruit to membranes different set of downstream effectors directly responsible for vesicle formation, movement, tethering and fusion (PubMed:9437002).
Plays a role in the initial events of the autophagic vacuole development which take place at specialized regions of the endoplasmic reticulum (PubMed:20545908).
Regulates vesicular transport between the endoplasmic reticulum and successive Golgi compartments (By similarity).
Required to modulate the compacted morphology of the Golgi (PubMed:26209634).
Promotes the recruitment of lipid phosphatase MTMR6 to the endoplasmic reticulum-Golgi intermediate compartment (By similarity).

Biological Process

Biological Process autophagosome assemblyManual Assertion Based On ExperimentIBA:GO_Central
Biological Process endoplasmic reticulum to Golgi vesicle-mediated transportManual Assertion Based On ExperimentIGI:UniProtKB
Biological Process Golgi organizationManual Assertion Based On ExperimentIMP:UniProtKB
Biological Process intracellular protein transportManual Assertion Based On ExperimentIBA:GO_Central
Biological Process positive regulation of glycoprotein metabolic processManual Assertion Based On ExperimentIGI:UniProtKB
Biological Process regulation of autophagosome assemblyManual Assertion Based On ExperimentIMP:UniProtKB
Biological Process virion assemblyManual Assertion Based On ExperimentIGI:UniProtKB

Cellular Location

Cytoplasm
Membrane
Preautophagosomal structure membrane
Cytoplasm, perinuclear region
Targeted by REP1 to membranes of specific subcellular compartments including endoplasmic reticulum, Golgi apparatus, and intermediate vesicles between these two compartments (PubMed:11389151).
In the GDP-form, colocalizes with GDI in the cytoplasm (PubMed:11389151).
Co-localizes with MTMR6 to the endoplasmic reticulum-Golgi intermediate compartment and to the peri-Golgi region (By similarity).

PTM

Prenylated; by GGTase II, only after interaction of the substrate with Rab escort protein 1 (REP1).
(Microbial infection) AMPylation at Tyr-77 by L.pneumophila DrrA occurs in the switch 2 region and leads to moderate inactivation of the GTPase activity. It appears to prolong the lifetime of the GTP state of RAB1B by restricting access of GTPase effectors to switch 2 and blocking effector-stimulated GTP hydrolysis, thereby rendering RAB1B constitutively active. It is later de-AMPylated by L.pneumophila SidD, releasing RAB1B from bacterial phagosomes.
(Microbial infection) Phosphocholinated at Ser-76 by L.pneumophila AnkX, leading to displace GDP dissociation inhibitors (GDI) (PubMed:21822290, PubMed:22307087).
Both GDP-bound and GTP-bound forms can be phosphocholinated. Dephosphocholinated by L.pneumophila Lem3, restoring accessibility to L.pneumophila GTPase effector LepB (PubMed:22158903, PubMed:22307087).
(Microbial infection) Glycosylated by S.typhimurium protein Ssek3: arginine GlcNAcylation prevents GTPase activity, thereby disrupting vesicular protein transport from the endoplasmic reticulum (ER) to the Golgi compartment.