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: 4.47). 04/2008; 19(3):971-83. DOI: 10.1091/mbc.E07-06-0551
Source: PubMed


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.

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    • "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). "
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    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 · 4.47 Impact Factor
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    • "Rab GTPases are major organizers of intracellular membrane trafficking in eukaryotic cells (Stenmark, 2009). Rab13 and Rab14 play important roles in tight junction formation and maintenance (Marzesco et al., 2002; Morimoto et al., 2005; Yamamura et al., 2008; Lu et al., 2014), and knockdown of Rab14 results in loss of claudin-2 from the cells (Lu et al., 2014). However, there are limited FIGURE 5: (A) ELISA shows that PKCι interacts with Rab14 in a high-affinity and saturable manner. "
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    ABSTRACT: PKCι is essential for the establishment of epithelial polarity and for the normal assembly of tight junctions. We find that PKCι knockdown does not compromise the steady state distribution of most tight junction proteins but results in increased transepithelial resistance (TER) and decreased paracellular permeability. Analysis of the levels of tight junction components demonstrates that claudin-2 protein levels are decreased. However, other tight junction proteins such as claudin-1, ZO-1 and occludin are unchanged. Incubation with an aPKC pseudosubstrate recapitulates the phenotype of PKCι knock down, including increased TER and decreased levels of claudin-2. In addition, overexpression of PKCι results in increased claudin-2 levels. ELISA and coimmunoprecipitation show that the TGN/endosomal small GTPase Rab14 and PKCι interact directly. Immunolabeling shows that PKCι and Rab14 colocalize in both intracellular puncta and at the plasma membrane and that Rab14 expression is required for normal PKCι distribution in cysts in 3D culture. We have shown previously that knockdown of Rab14 results in increased TER and decreased claudin-2. Our results suggest that Rab14 and aPKC interact to regulate trafficking of claudin-2 out of the lysosome directed pathway. © 2015 by The American Society for Cell Biology.
    Molecular Biology of the Cell 02/2015; 26(8). DOI:10.1091/mbc.E14-12-1613 · 4.47 Impact Factor
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    • "Only 2 of the 60 Rabs can be detected in the vicinity of tight junctions in epithelia (Marzesco and Zahraoui, 2005; Weber et al., 1994). In particular Rabs 3 and 13 are required for the dynamic endocytic recycling of Occludin and Claudin-1 to the cell surface (Morimoto et al., 2005; Yamamura et al., 2008; Yamamoto et al., 2003). Save for a role for Rab3A in melanosome transport in melanocytes (Scott and Zhao, 2001), nothing is known about the expression and function of these Rabs in epidermal barrier acquisition. "
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    ABSTRACT: Epidermal barrier acquisition during late murine gestation is accompanied by an increase in Akt kinase activity and cJun dephosphorlyation. The latter is directed by the Ppp2r2a regulatory subunit of the Pp2a phosphatase. This was accompanied by a change of Claudin-1 localisation to the cell surface and interaction between Occludin and Claudin-1 which are thought to be required for tight junction formation. The aim of this study was to determine the nature of the barrier defect caused by the loss of AKT/Ppp2r2a function. There was a paracellular barrier defect in rat epidermal keratinocytes expressing a Ppp2r2a siRNA. In Ppp2r2a knockdown cells, Claudin-1 was located to the cytoplasm and its expression was increased. Inhibiting cJun phosphorylation restored barrier function and plasma membrane localisation of Claudin-1. Expression of the Rab3 GTPase activating protein, Rab3Gap1, was restored in Ppp2r2a siRNA cells when cJun phosphorylation was inhibited. During normal mouse epidermal development, Claudin-1 plasma membrane localisation and Rab3Gap1 cell surface expression were co-incident with Akt activation in mouse epidermis, strongly suggesting a role of Rab3Gap1 in epidermal barrier acquisition. Supporting this hypothesis, siRNA knockdown of Rab3Gap1 prevented plasma membrane Claudin-1 expression and the formation of a barrier competent epithelium. Replacing Rab3Gap1 in Ppp2r2a knockdown cells was sufficient to rescue Claudin-1 transport to the cell surface. Therefore these data suggest Rab3Gap1 mediated exocytosis of Claudin-1 is an important component of epidermal barrier acquisition during epidermal development.
    Developmental Biology 05/2013; 380(2). DOI:10.1016/j.ydbio.2013.04.034 · 3.55 Impact Factor
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