Article

The Interaction of JRAB/MICAL-L2 with Rab8 and Rab13 Coordinates the Assembly of Tight Junctions and Adherens Junctions

Department of Biochemistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
Molecular biology of the cell (Impact Factor: 5.98). 04/2008; 19(3):971-83. DOI: 10.1091/mbc.E07-06-0551
Source: PubMed

ABSTRACT The assembly of tight junctions (TJs) and adherens junctions (AJs) is regulated by the transport of integral TJ and AJ proteins to and/or from the plasma membrane (PM) and it is tightly coordinated in epithelial cells. We previously reported that Rab13 and a junctional Rab13-binding protein (JRAB)/molecule interacting with CasL-like 2 (MICAL-L2) mediated the endocytic recycling of an integral TJ protein occludin and the formation of functional TJs. Here, we investigated the role of Rab13 and JRAB/MICAL-L2 in the transport of other integral TJ and AJ proteins claudin-1 and E-cadherin to the PM by using a Ca(2+)-switch model. Although knockdown of Rab13 specifically suppressed claudin-1 and occludin but not E-cadherin transport, knockdown of JRAB/MICAL-L2 and expression of its Rab13-binding domain (JRAB/MICAL-L2-C) inhibited claudin-1, occludin, and E-cadherin transport. We then identified Rab8 as another JRAB/MICAL-L2-C-binding protein. Knockdown of Rab8 inhibited the Rab13-independent transport of E-cadherin to the PM. Rab8 and Rab13 competed with each other for the binding to JRAB/MICAL-L2 and functionally associated with JRAB/MICAL-L2 at the perinuclear recycling/storage compartments and PM, respectively. These results suggest that the interaction of JRAB/MICAL-L2 with Rab8 and Rab13 coordinates the assembly of AJs and TJs.

0 Followers
 · 
160 Views
    • "Endocytic membrane trafficking is essential for maintenance of TJ integrity (Ivanov et al., 2005; Morimoto et al., 2005; Terai et al., 2006; Yamamura et al., 2008; Marchiando et al., 2010) and epithelial polarity, and disruption of membrane trafficking induces a loss of polarity and an overgrowth phenotype (Lu and Bilder, 2005). Endotubin (EDTB; also known as MAMDC4, AEGP) is an integral membrane protein that localizes to specialized apical endosomes (Wilson et al., 1987, 2000; Wilson and Colton, 1997; Gokay and Wilson, 2000). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Contact-mediated inhibition of cell proliferation is an essential part of organ growth control; the transcription coactivator Yes-associated protein (YAP) plays a pivotal role in this process. In addition to phosphorylation-dependent regulation of YAP, the integral membrane protein Angiomotin (AMOT) and AMOT family members control YAP through direct binding. Here we report that regulation of YAP activity occurs at the endosomal membrane through a dynamic interaction of AMOT with an endosomal integral membrane protein endotubin (EDTB). EDTB interacts with both AMOT and occludin and preferentially associates with occludin in confluent cells but with AMOT family members in subconfluent cells. EDTB competes with YAP for binding to AMOT proteins in subconfluent cells. Over-expression of the cytoplasmic domain or full-length EDTB induces translocation of YAP to the nucleus, an overgrowth phenotype and growth in soft agar. This increase in proliferation is dependent upon YAP activity and is complemented by overexpression of p130-AMOT. Furthermore, overexpression of EDTB inhibits the AMOT:YAP interaction. EDTB and AMOT have a greater association in subconfluent cells compared with confluent cells, and this association is regulated at the endosomal membrane. These data provide a link between the trafficking of tight junction proteins through endosomes and contact-inhibition-regulated cell growth. © 2015 by The American Society for Cell Biology.
    Molecular biology of the cell 05/2015; 26(14). DOI:10.1091/mbc.E15-04-0224 · 5.98 Impact Factor
  • Source
    • "JFC1 is a member of the Slp family of proteins and was originally identified as a novel C2 domain protein that interacted with NADPH oxidase (McAdara Berkowitz et al., 2001) and as an effector that binds Rab27a (Strom et al., 2002). The second Rab8a effector we used is molecule interacting with CasL-like 1 (MICAL-L1; Fukuda et al., 2008; Yamamura et al., 2008). To explore whether these effectors influence vacuole formation induced by EPI64 overexpression , we coexpressed each with HXP-EPI64 in HeLa cells. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cell function requires the integration of cytoskeletal organization and membrane trafficking. Small GTP-binding proteins are key regulators of these processes. We find that EPI64, an apical microvillar protein with a Tre-2/Bub2/Cdc16 (TBC) domain that stabilizes active Arf6 and has RabGAP activity, regulates Arf6-dependent membrane trafficking. Expression of EPI64 in HeLa cells induces the accumulation of actin-coated vacuoles, a distinctive phenotype seen in cells expressing constitutively active Arf6. Expression of EPI64 with defective RabGAP activity does not induce vacuole formation. Coexpression of Rab8a suppresses the vacuole phenotype induced by EPI64, and EPI64 expression lowers the level of Rab8-GTP in cells, strongly suggesting that EPI64 has GAP activity toward Rab8a. JFC1, an effector for Rab8a, colocalizes with and binds directly to a C-terminal region of EPI64. Together this region and the N-terminal TBC domain of EPI64 are required for the accumulation of vacuoles. Through analysis of mutants that uncouple JFC1 from either EPI64 or from Rab8-GTP, our data suggest a model in which EPI64 binds JFC1 to recruit Rab8a-GTP for deactivation by the RabGAP activity of EPI64. We propose that EPI64 regulates membrane trafficking both by stabilizing Arf6-GTP and by inhibiting the recycling of membrane through the tubular endosome by decreasing Rab8a-GTP levels.
    Molecular biology of the cell 01/2012; 23(4):701-15. DOI:10.1091/mbc.E11-06-0521 · 5.98 Impact Factor
  • Source
    • "membrane protein, occludin (Morimoto et al., 2005; Terai et al., 2006; Yamamura et al., 2008). Neither silencing MICAL-L1 nor its overexpression affects EGFR ubiquitination. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Small GTPase Rabs are required for membrane protein sorting/delivery to precise membrane domains. Rab13 regulates epithelial tight junction assembly and polarized membrane transport. Here we report that Molecule Interacting with CasL (MICAL)-like1 (MICAL-L1) interacts with GTP-Rab13 and shares a similar domain organization with MICAL. MICAL-L1 has a calponin homology (CH), LIM, proline rich and coiled-coil domains. It is associated with late endosomes. Time-lapse video microscopy shows that green fluorescent protein-Rab7 and mcherry-MICAL-L1 are present within vesicles that move rapidly in the cytoplasm. Depletion of MICAL-L1 by short hairpin RNA does not alter the distribution of a late endosome/lysosome-associated protein but affects the trafficking of epidermal growth factor receptor (EGFR). Overexpression of MICAL-L1 leads to the accumulation of EGFR in the late endosomal compartment. In contrast, knocking down MICAL-L1 results in the distribution of internalized EGFR in vesicles spread throughout the cytoplasm and promotes its degradation. Our data suggest that the N-terminal CH domain associates with the C-terminal Rab13 binding domain (RBD) of MICAL-L1. The binding of Rab13 to RBD disrupts the CH/RBD interaction, and may induce a conformational change in MICAL-L1, promoting its activation. Our results provide novel insights into the MICAL-L1/Rab protein complex that can regulate EGFR trafficking at late endocytic pathways.
    Molecular biology of the cell 07/2011; 22(18):3431-41. DOI:10.1091/mbc.E11-01-0030 · 5.98 Impact Factor
Show more

Preview

Download
2 Downloads
Available from