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Article: Interactions among IQGAP1, cdc42, and the cadherin/catenin protein complex regulate Sertoli-germ cell adherens junction dynamics in the testis

TitleInteractions among IQGAP1, cdc42, and the cadherin/catenin protein complex regulate Sertoli-germ cell adherens junction dynamics in the testis
Authors
Issue Date2005
PublisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/31010
Citation
Journal of Cellular Physiology, 2005, v. 202 n. 1, p. 49-66 How to Cite?
AbstractThe movement of developing germ cells across the seminiferous epithelium during spermatogenesis involves extensive adherens junction (AJ) restructuring between Sertoli cells, as well as between Sertoli and germ cells. In this report, we show that the intricate interactions between Cdc42 (a Rho family protein of Mr approximately 23 kDa originally identified in membranes of human platelets and placenta, and is the homolog of CDC42Sc, which is known to regulate of bud-site assembly in Saccharomyces cerevisiae) and its effector, IQ motif containing GTPase activating protein (IQGAP1, Mr approximately 189 kDa, it is also an actin-binding protein known to interact with Cdc42 and Rac1 GTPases), regulate Sertoli-germ cell, but not Sertoli-Sertoli cell, AJ dynamics. Using testis lysates for immunoprecipitation (IP), IQGAP1 was shown to associate with E-cadherin, N-cadherin, and beta-catenin (but not beta1-integrin and nectin-2), as well as with actin and vimentin (but not alpha-tubulin). Moreover, IQGAP1 was found to localize to the periphery of both Sertoli and germ cells in the seminiferous epithelium, at sites of cell-cell contacts. Using fluorescent microscopy with dual fluorescent probes, IQGAP1 was found to co-localize, at least in part, with N-cadherin in the seminiferous epithelium consistent with their localization at the basal and apical ES. Using Sertoli-germ cell cocultures, it was demonstrated that AJ assembly associated with a transient induction of Cdc42 and IQGAP1, which was not found when Sertoli cells were cultured alone. Lastly, a shift in the interactions of Cdc42, IQGAP1, beta-catenin, and N-cadherin was detected in Sertoli-germ cell cocultures using an Ca2+-induced AJ disruption model, which was used to examine AJ disassembly and its reassembly. In the presence of Ca2+, IQGAP1 bound preferentially to Cdc42 rather than to beta-catenin. However, when Ca2+ was depleted from cocultures using EGTA, a Ca2+ chelating agent, IQGAP1 lost its affinity for Cdc42 and became tightly associated with beta-catenin, destabilizing cadherin-mediated AJs between Sertoli and germ cells. Yet this shift of protein-protein interaction was not detected in Sertoli cells cultured alone. These results illustrate that the interactions among IQGAP1, Cdc42, and beta-catenin are crucial to the regulation of Sertoli-germ cell, but not Sertoli-Sertoli cell, AJ dynamics in the seminiferous epithelium.
Persistent Identifierhttp://hdl.handle.net/10722/84602
ISSN
2015 Impact Factor: 4.155
2015 SCImago Journal Rankings: 1.842
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorLui, WYen_HK
dc.contributor.authorMruk, DDen_HK
dc.contributor.authorCheng, CYen_HK
dc.date.accessioned2010-09-06T08:54:57Z-
dc.date.available2010-09-06T08:54:57Z-
dc.date.issued2005en_HK
dc.identifier.citationJournal of Cellular Physiology, 2005, v. 202 n. 1, p. 49-66en_HK
dc.identifier.issn0021-9541en_HK
dc.identifier.urihttp://hdl.handle.net/10722/84602-
dc.description.abstractThe movement of developing germ cells across the seminiferous epithelium during spermatogenesis involves extensive adherens junction (AJ) restructuring between Sertoli cells, as well as between Sertoli and germ cells. In this report, we show that the intricate interactions between Cdc42 (a Rho family protein of Mr approximately 23 kDa originally identified in membranes of human platelets and placenta, and is the homolog of CDC42Sc, which is known to regulate of bud-site assembly in Saccharomyces cerevisiae) and its effector, IQ motif containing GTPase activating protein (IQGAP1, Mr approximately 189 kDa, it is also an actin-binding protein known to interact with Cdc42 and Rac1 GTPases), regulate Sertoli-germ cell, but not Sertoli-Sertoli cell, AJ dynamics. Using testis lysates for immunoprecipitation (IP), IQGAP1 was shown to associate with E-cadherin, N-cadherin, and beta-catenin (but not beta1-integrin and nectin-2), as well as with actin and vimentin (but not alpha-tubulin). Moreover, IQGAP1 was found to localize to the periphery of both Sertoli and germ cells in the seminiferous epithelium, at sites of cell-cell contacts. Using fluorescent microscopy with dual fluorescent probes, IQGAP1 was found to co-localize, at least in part, with N-cadherin in the seminiferous epithelium consistent with their localization at the basal and apical ES. Using Sertoli-germ cell cocultures, it was demonstrated that AJ assembly associated with a transient induction of Cdc42 and IQGAP1, which was not found when Sertoli cells were cultured alone. Lastly, a shift in the interactions of Cdc42, IQGAP1, beta-catenin, and N-cadherin was detected in Sertoli-germ cell cocultures using an Ca2+-induced AJ disruption model, which was used to examine AJ disassembly and its reassembly. In the presence of Ca2+, IQGAP1 bound preferentially to Cdc42 rather than to beta-catenin. However, when Ca2+ was depleted from cocultures using EGTA, a Ca2+ chelating agent, IQGAP1 lost its affinity for Cdc42 and became tightly associated with beta-catenin, destabilizing cadherin-mediated AJs between Sertoli and germ cells. Yet this shift of protein-protein interaction was not detected in Sertoli cells cultured alone. These results illustrate that the interactions among IQGAP1, Cdc42, and beta-catenin are crucial to the regulation of Sertoli-germ cell, but not Sertoli-Sertoli cell, AJ dynamics in the seminiferous epithelium.-
dc.languageengen_HK
dc.publisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/31010en_HK
dc.relation.ispartofJournal of Cellular Physiologyen_HK
dc.rightsJournal of Cellular Physiology. Copyright © John Wiley & Sons, Inc.en_HK
dc.titleInteractions among IQGAP1, cdc42, and the cadherin/catenin protein complex regulate Sertoli-germ cell adherens junction dynamics in the testisen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0021-9541&volume=202&spage=49&epage=66&date=2005&atitle=Interactions+among+IQGAP1,+cdc42,+and+the+cadherin/catenin+protein+complex+regulate+Sertoli-germ+cell+adherens+junction+dynamics+in+the+testisen_HK
dc.identifier.emailLui, WY: wylui@hku.hken_HK
dc.identifier.authorityLui, WY=rp00756en_HK
dc.identifier.doi10.1002/jcp.20098-
dc.identifier.pmid15389538-
dc.identifier.hkuros100781en_HK
dc.identifier.isiWOS:000225514300006-

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