Alternative titles; symbols
HGNC Approved Gene Symbol: RAB2A
Cytogenetic location: 8q12.1-q12.2 Genomic coordinates (GRCh38): 8:60,516,910-60,623,644 (from NCBI)
Members of the Rab protein family are nontransforming monomeric GTP-binding proteins of the Ras superfamily that contain 4 highly conserved regions involved in GTP binding and hydrolysis. Rabs are prenylated, membrane-bound proteins involved in vesicular fusion and trafficking. The mammalian RAB proteins show striking similarities to the S. cerevisiae YPT1 and SEC4 proteins, Ras-related GTP-binding proteins involved in the regulation of secretion.
Zahraoui et al. (1989) isolated cDNAs encoding RAB2 and several other human RAB proteins. See RAB5A (179512). The predicted 212-amino acid human RAB2 protein shares 98% identity with rat Rab2. Northern blot analysis revealed that the RAB2 gene was expressed as 1.1-, 2.5-, and 3.6-kb mRNAs in a human fibroblast cell line.
Tisdale and Balch (1996) stated that the RAB2 protein is a resident of pre-Golgi intermediates and is required for protein transport from the endoplasmic reticulum to the Golgi complex. They found that RAB2 is essential for the maturation of pre-Golgi intermediates.
Using stable human cell lines expressing RAB2, Ding et al. (2019) showed that Golgi-resident RAB2 relocated to autophagic membrane structures through microtubule-based vesicular transport upon autophagy induction. Knockout analysis in U2OS cells suggested that RAB2 regulated autophagy initiation in the process, as autophagy induction liberated a population of RAB2-containing vesicles from the Golgi network for autophagy initiation. Autophagy induction triggered RAB2-mediated ULK1 (603168) acquisition and activation to facilitate formation of a phagophore for autophagy initiation. RAB2 also interacted and colocalized with RUBCNL (620175) and STX17 (604204) to become an autophagosomal GTPase, and RUBCNL and STX17 prevented GDI2 (600767)-mediated membrane extraction to maintain RAB2 on autophagosomes. Furthermore, the autophagosomal trimeric complex containing RAB2, STX17, and RUBCNL specified recruitment of the HOPS complex (see 605485) to facilitate autophagosome maturation.
By analysis of the human genome database, Ni et al. (2002) mapped the RAB2A gene to chromosome 8q12.1 and the RAB2B gene (607466) to 14q11.1-q11.2.
Ding, X., Jiang, X., Tian, R., Zhao, P., Li, L., Wang, X., Chen, S., Zhu, Y., Mei, M., Bao, S., Liu, W., Tang, Z., Sun, Q. RAB2 regulates the formation of autophagosome and autolysosome in mammalian cells. Autophagy 15: 1774-1786, 2019. [PubMed: 30957628] [Full Text: https://doi.org/10.1080/15548627.2019.1596478]
Ni, X., Ma, Y., Cheng, H., Jiang, M., Guo, L., Ji, C., Gu, S., Cao, Y., Xie, Y., Mao, Y. Molecular cloning and characterization of a novel human Rab (Rab2B) gene. J. Hum. Genet. 47: 548-551, 2002. [PubMed: 12376746] [Full Text: https://doi.org/10.1007/s100380200083]
Tisdale, E. J., Balch, W. E. Rab2 is essential for the maturation of pre-Golgi intermediates. J. Biol. Chem. 271: 29372-29379, 1996. [PubMed: 8910601] [Full Text: https://doi.org/10.1074/jbc.271.46.29372]
Zahraoui, A., Touchot, N., Chardin, P., Tavitian, A. The human rab genes encode a family of GTP-binding proteins related to yeast YPT1 and SEC4 products involved in secretion. J. Biol. Chem. 264: 12394-12401, 1989. [PubMed: 2501306]