MgcRacGAP interacts with cingulin and paracingulin to regulate Rac1 activation and development of the tight junction barrier during epithelial junction assembly

Article Article scientifique Article MgcRacGAP interacts with cingulin and paracingulin to regulate Rac1 activation and development of the tight junction barrier during epithelial junction assembly eng 2014-05-07 2014-07-01 author Guillemot Laurent Michel Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland 543257 author Guerrera Diego 0000-0002-5323-4447 Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland 793899 author Spadaro Domenica Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland 732150 author Tapia Pastrana Rocio Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland 765614 author Jond Lionel Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland 96467 Département de biologie moléculaire et cellulaire (MOCEL) author Citi Sandra 0000-0002-6537-4818 Department of Molecular Biology, University of Geneva, CH-1211 Geneva, Switzerland 116085 Département de biologie moléculaire et cellulaire (MOCEL) 1995-2005 10.1091/mbc.E13-11-0680 24807907 1059-1524 PMC4072573 https://www.molbiolcell.org/doi/10.1091/mbc.e13-11-0680 <p>The regulation of Rho-family GTPases is crucial to direct the formation of cell–cell junctions and tissue barriers. Cingulin (CGN) and paracingulin (CGNL1) control RhoA activation in epithelial cells by interacting with RhoA guanidine exchange factors. CGNL1 depletion also inhibits Rac1 activation during junction assembly. Here we show that, unexpectedly, Madin–Darby canine kidney epithelial cells depleted of both CGN and CGNL1 (double-KD cells) display normal Rac1 activation and tight junction (TJ) formation, despite decreased junctional recruitment of the Rac1 activator Tiam1. The expression of the Rac1 inhibitor MgcRacGAP is decreased in double-KD cells, and the barrier development and Rac1 activation phenotypes are rescued by exogenous expression of MgcRacGAP. MgcRacGAP colocalizes with CGN and CGNL1 at TJs and forms a complex and interacts directly in vitro with CGN and CGNL1. Depletion of either CGN or CGNL1 in epithelial cells results in decreased junctional localization of MgcRacGAP but not of ECT2, a centralspindlin-interacting Rho GEF. These results provide new insight into coordination of Rho-family GTPase activities at junctions, since apical accumulation of CGN and CGNL1 at TJs during junction maturation provides a mechanism to spatially restrict down-regulation of Rac1 activation through the recruitment of MgcRacGAP.</p> Animals Coculture Techniques Cytoskeletal Proteins / metabolism Dogs Enzyme Activation Epithelium GTPase-Activating Proteins / metabolism Humans Keratinocytes / metabolism MCF-7 Cells Madin Darby Canine Kidney Cells Membrane Proteins / metabolism Mice, Knockout Microfilament Proteins / metabolism Protein Multimerization Tight Junctions / metabolism Rac1 GTP-Binding Protein / metabolism Dewey 590 Dewey 570 Swiss National Science Foundation The functions of the tight junction-associated proteins cingulin and paracingulin 116763 CH Projects Swiss National Science Foundation The functions of cingulin, paracingulin and PLEKHA7 at epithelial junctions 135730 CH Projects Swiss National Science Foundation Signaling at epithelial apical junctions 152899 CH Projects Swiss Cancer League KFS-2813-08-2011 43 Département de biologie moléculaire 161 46 Département de biologie cellulaire 165 23 Institut de génétique et de génomique 0DH false 1441 Groupe Citi Molecular biology of the cell 25 13 c079f2f9-b87d-42e0-920b-5e31754ad380 Article (Published version) Public CITI06.pdf 1971666 application/pdf CC BY-NC-SA-3.0 c6676031e6aa4fead1590720e6dbe3225aa7855e25ebcbfe5718db55d8cf3649 c0901cf5-4c8b-4b4f-b637-3c1baffa7197 Appendix Public supp_E13-11-0680v1_CombinedSupMats.pdf 14615905 application/pdf 73d5e6469ea5adbaef25363788c795428f8c177033c57a4343d76685c332a7bb openAccess Faculté des sciences / Section de biologie / Département de biologie moléculaire Faculté des sciences / Section de biologie / Département de biologie cellulaire Centres et instituts / Institut de génétique et de génomique

Title	Published in	Year	Views	Downloads

ZO Proteins Redundantly Regulate the Transcription Factor DbpA/ZONAB	The Journal of biological chemistry	2014	83	44
MgcRacGAP interacts with cingulin and paracingulin to regulate Rac1 activation and development of the tight junction barrier during epithelial junction assembly	Molecular biology of the cell	2014	73	182

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