title: Distinct roles of Rab3B and Rab13 in the polarized transport of apical, basolateral, and tight junctional membrane proteins to the plasma membrane.
abstract: Regulated transport of proteins to distinct plasma membrane domains is essential for the establishment and maintenance of cell polarity in all eukaryotic cells. The Rab family small G proteins play a crucial role in determining the specificity of vesicular transport pathways. Rab3B and Rab13 localize to tight junction in polarized epithelial cells and cytoplasmic vesicular structures in non-polarized fibroblasts, but their functions are poorly understood. Here we examined their roles in regulating the cell-surface transport of apical p75 neurotrophin receptor (p75NTR), basolateral low-density lipoprotein receptor (LDLR), and tight junctional Claudin-1 using transport assay in non-polarized fibroblasts. Overexpression of Rab3B mutants inhibited the cell-surface transport of LDLR, but not p75NTR and Claudin-1. In contrast, overexpression of Rab13 mutants impaired the transport of Claudin-1, but not LDLR and p75NTR. These results suggest that Rab3B and Rab13 direct the cell-surface transport of LDLR and Claudin-1, respectively, and may contribute to epithelial polarization.
authors.affiliation: Department of Biochemistry, The University of Tokushima, Graduate School of Medicine, Tokushima 770-8503, Japan.
authors.forename: Yasuyo
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nishimura
authors.forename: Shinya
authors.initials: S
authors.lastname: Morimoto
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kitamura
authors.forename: Shinji
authors.initials: S
authors.lastname: Manabe
authors.forename: Hiro-omi
authors.initials: HO
authors.lastname: Kanayama
authors.forename: Susumu
authors.initials: S
authors.lastname: Kagawa
authors.forename: Takuya
authors.initials: T
authors.lastname: Sasaki
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D018938:Caco-2 Cells; D002417:Cattle; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D062445:Claudin-1; D006224:Cricetinae; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D016297:Mutagenesis, Site-Directed; D020800:Receptor, Nerve Growth Factor; D011973:Receptors, LDL / Q000378:metabolism; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D019108:Tight Junctions / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020692:rab3 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: C568108:CLDN1 protein, human; D062445:Claudin-1; C568113:Cldn1 protein, mouse; D008565:Membrane Proteins; D020800:Receptor, Nerve Growth Factor; D011973:Receptors, LDL; D017475:Receptors, Nerve Growth Factor; D011994:Recombinant Proteins; C085485:RAB13 protein, human; C492131:RAB3B protein, human; C484177:Rab13 protein, mouse; C116709:Rab3b protein, mouse; D020691:rab GTP-Binding Proteins; D020692:rab3 GTP-Binding Proteins