<b>Rab3A small GTP‐binding protein in Ca<sup>2+</sup>‐dependent exocytosis</b>

Takai, Yoshimi; Sasaki, Takuya; Shirataki, Hiromichi; Nakanishi, Hiroyuki

doi:10.1046/j.1365-2443.1996.00257.x

Cited by 103 publications

(90 citation statements)

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“…We have recently shown in MDCK cells that Rab GDP dissociation inhibitor (GDI) regulates the TPA-induced reorganization of stress ®bers and focal adhesions (Imamura et al, 1998). Rab GDI is a general regulator of all the Rab family members (for reviews, see Takai et al, 1996;Novick and Zerial, 1997). Of the Rab family members, Rab5 regulates early endocytosis (Bucci et al, 1992;Stenmark et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Coendocytosis of cadherin and c-Met coupled to disruption of cell-cell adhesion in MDCK cells – regulation by Rho, Rac and Rab small G proteins

et al. 1999

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Both E-cadherin, a cell-cell adhesion molecule, and cMet, the hepatocyte growth factor (HGF)/scatter factor (SF) receptor, were colocalized at cell-cell adhesion sites of MDCK cells. HGF/SF or a phorbol ester, 12-Otetradecanoylphorbol-13-acetate (TPA), induced disruption of cell-cell adhesion, which was accompanied by endocytosis of both E-cadherin and c-Met. Reduction of medium Ca 2+ to a micromolar range showed the same e ects. Re-increase in medium Ca 2+ to a millimolar range formed cell-cell adhesion, which was accompanied by exocytosis of E-cadherin and c-Met, followed by their re-colocalization at the cell-cell adhesion sites. These results suggest that E-cadherin and c-Met are colocalized at cell-cell adhesion sites and undergo co-endo-exocytosis. We have previously shown that TPA does not induce disruption of cell-cell adhesion and subsequent scattering of MDCK cells stably expressing a dominant active mutant of RhoA or Rac1 small G protein or a dominant negative mutant of Rab5 small G protein. In these cell lines, the HGF-or TPA-induced coendocytosis of E-cadherin and c-Met was inhibited, but the coendocytosis of E-cadherin and c-Met in response to reduction of medium Ca 2+ was not a ected. Wortmannin, an inhibitor of phosphoinositide (PI) 3-kinase, inhibited the HGF-induced disruption of cell-cell junction and endocytosis of E-cadherin and c-Met, but not the TPA-induced ones. These results suggest that disruption of cell-cell adhesion is involved in the HGF-or TPAinduced coendocytosis of E-cadherin and c-Met in MDCK cells, and that the Rho and Rab family members indirectly regulate this coendocytosis. In addition, coendocytosis of E-cadherin and c-Met in response to HGF is partly mediated by PI 3-kinase. The cross-talk between cell-cell and cell-matrix adherens junctions is discussed.

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Section: Introductionmentioning

confidence: 99%

Coendocytosis of cadherin and c-Met coupled to disruption of cell-cell adhesion in MDCK cells – regulation by Rho, Rac and Rab small G proteins

et al. 1999

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“…The Rab small G protein family is implicated in intracellular vesicle tra cking and Rab5 is involved in endocytosis (Bucci et al, 1992;Stenmark et al, 1994;for review, see Novick and Zerial, 1997). Rab GDI is a general regulator of all the Rab family members (for reviews, see Takai et al, 1996;Novick and Zerial;. The function of the Rab family in cell adhesion and migration may be related to endo-exocytosis of adhesion molecules such as integrins.…”

Section: Introductionmentioning

confidence: 99%

Involvement of Cdc42 small G protein in cell-cell adhesion, migration and morphology of MDCK cells

et al. 1999

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The Rho small G protein family consists of the Rho, Rac, and Cdc42 subfamilies and regulates various cell functions through reorganization of the actin cytoskeleton. We previously showed that the Rho subfamily regulates the formation of stress ®bers and focal adhesions whereas the Rac subfamily regulates the Ecadherin-based cell-cell adhesion in MDCK cells. We studied here the function of the Cdc42 subfamily, consisting of two members, Cdc42Hs and G25k, in cell adhesion, migration, and morphology of MDCK cells. For this purpose, we made and used MDCK cell lines stably expressing each of dominant active mutants of Cdc42Hs (sMDCK-Cdc42HsDA) and G25K (sMDCK-G25KDA). Actin ®laments at the cell-cell adhesion sites increased in both sMDCK-Cdc42HsDA and -G25KDA cells. Both E-cadherin and b-catenin, adherens junctional proteins, at the cell-cell adhesion sites also increased in both sMDCK-Cdc42HsDA and -G25KDA cells. Electron microscopic analysis revealed that sMDCKCdc42HsDA cells tightly contacted with each other throughout the lateral membranes. Moreover, both the HGF-and TPA-induced disruption of the cadherin-based cell-cell adhesion and the subsequent cell migration were inhibited in both sMDCK-Cdc42HsDA and -G25KDA cells. Co-expression of the dominant negative mutant of Rac1, a member of the Rac subfamily, with the dominant active mutant of Cdc42Hs did not inhibit the increased accumulation of actin ®laments at the cell-cell adhesion sites. These results suggest that the Cdc42 subfamily is involved in the cadherin-based cell-cell adhesion in a manner independent of the Rac subfamily. Furthermore, the cells were frequently enveloped by the large multinuclear cells in both sMDCK-Cdc42HsDA and -G25KDA cells. Video microscopic analysis revealed that the cells were engulfed by the large cells during cytokinesis.

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“…The superfamily in mammalian cells consists of six families: Ras, Rho, Rab, Arf, Sar1 and Ran (Hall, 1994;Takai et al, 1996). Proteins belonging to the superfamily contain structural motifs involved in GDP/GTP-binding and GTPase activity, which are highly conserved among them and divided into four regions (Bourne et al, 1991;Valencia et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

“…To date more than ten members each of the Ras and Rho families have been identi®ed (Hall, 1994;Takai et al, 1996). Primary functions of Ras family members are to control cell growth, di erentiation, transformation and apoptosis (Bollag and McCormick, 1991;Lowy and Willumsen, 1993;Lin et al, 1995;Wang et al, 1995;Trent et al, 1996), whereas those of Rho family members are to regulate organization of the actin cytoskeleton (Hall, 1994;Takai et al, 1995;Narumiya, 1996).…”

Section: Introductionmentioning

confidence: 99%

Novel small GTPase M-Ras participates in reorganization of actin cytoskeleton

1997

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Rab3A small GTP‐binding protein in Ca²⁺‐dependent exocytosis

Cited by 103 publications

References 104 publications

Coendocytosis of cadherin and c-Met coupled to disruption of cell-cell adhesion in MDCK cells – regulation by Rho, Rac and Rab small G proteins

Coendocytosis of cadherin and c-Met coupled to disruption of cell-cell adhesion in MDCK cells – regulation by Rho, Rac and Rab small G proteins

Involvement of Cdc42 small G protein in cell-cell adhesion, migration and morphology of MDCK cells

Novel small GTPase M-Ras participates in reorganization of actin cytoskeleton

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Rab3A small GTP‐binding protein in Ca2+‐dependent exocytosis

Cited by 103 publications

References 104 publications

Coendocytosis of cadherin and c-Met coupled to disruption of cell-cell adhesion in MDCK cells – regulation by Rho, Rac and Rab small G proteins

Coendocytosis of cadherin and c-Met coupled to disruption of cell-cell adhesion in MDCK cells – regulation by Rho, Rac and Rab small G proteins

Involvement of Cdc42 small G protein in cell-cell adhesion, migration and morphology of MDCK cells

Novel small GTPase M-Ras participates in reorganization of actin cytoskeleton

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Rab3A small GTP‐binding protein in Ca²⁺‐dependent exocytosis