Distinct roles of Rab3B and Rab13 in the polarized transport of apical, basolateral, and tight junctional membrane proteins to the plasma membrane.
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.
Yamamoto
Yasuyo
Y
Department of Biochemistry, The University of Tokushima, Graduate School of Medicine, Tokushima 770-8503, Japan.
Nishimura
Noriyuki
N
Morimoto
Shinya
S
Kitamura
Hiroko
H
Manabe
Shinji
S
Kanayama
Hiro-omi
HO
Kagawa
Susumu
S
Sasaki
Takuya
T
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
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