HGNC Approved Gene Symbol: RAB3B
Cytogenetic location: 1p32.3 Genomic coordinates (GRCh38): 1:51,907,956-51,990,700 (from NCBI)
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 RAB3B and several other human RAB proteins. The predicted 219-amino acid human RAB3B protein shares 78% identity with RAB3A (179490).
Polymeric immunoglobulin receptor (PIGR; 173880) binds its ligand, dimeric IgA (dIgA; see 146900), at the basolateral surface of epithelial cells. After endocytosis, the PIGR-dIgA complex traverses several endosomal compartments and is exocytosed at the apical plasma membrane. Van IJzendoorn et al. (2002) found that Rab3b localized to vesicular structures containing Pigr in canine kidney cells and that GTP-bound Rab3b interacted directly with the cytoplasmic domain of Pigr. Binding of dIgA to Pigr dissociated Rab3b, but a constitutively active Rab3b mutant maintained its interaction with Pigr in dIgA-treated cells. Furthermore, GTP-locked Rab3b inhibited dIgA-stimulated transcytosis.
Rousseau-Merck et al. (1989, 1991) used in situ hybridization to map RAB3B to 1p32-p31.
Rousseau-Merck, M. F., Zahraoui, A., Bernheim, A., Touchot, N., Miglierina, R., Tavitian, A., Berger, R. Chromosome mapping of the human RAS related RAB3A and RAB3B genes to chromosomes 19p13.2 and 1p31-p32, respectively. (Abstract) Cytogenet. Cell Genet. 51: 1070 only, 1989.
Rousseau-Merck, M. F., Zahraoui, A., Touchot, N., Tavitian, A., Berger, R. Chromosome assignment of four RAS-related RAB genes. Hum. Genet. 86: 350-354, 1991. [PubMed: 1999336] [Full Text: https://doi.org/10.1007/BF00201831]
van IJzendoorn, S. C. D., Tuvim, M. J., Weimbs, T., Dickey, B. F., Mostov, K. E. Direct interaction between Rab3b and the polymeric immunoglobulin receptor controls ligand-stimulated transcytosis in epithelial cells. Dev. Cell 2: 219-228, 2002. [PubMed: 11832247] [Full Text: https://doi.org/10.1016/s1534-5807(02)00115-6]
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]