title: Involvement of caveolin-1 in fibronectin-induced mouse embryonic stem cell proliferation: role of FAK, RhoA, PI3K/Akt, and ERK 1/2 pathways.
abstract: Fibronectin (FN) is the foremost proliferation-associated extracellular matrix component promoting cell adhesion, migration, and survival. We examined the effect of FN on cell proliferation and the related signaling pathways in mouse embryonic stem (ES) cells. FN increased integrin β1, Src, focal adhesion kinase (FAK), and caveolin-1 phosphorylation levels in a time-dependent manner. Phosphorylation of Src, FAK, and caveolin-1 was attenuated by integrin β1 neutralizing antibody. Integrin β1, Src, and FAK coimmunoprecipitated with caveolin-1 in the presence of FN. In addition, FN increased RhoA and Rho kinase activation, which were completely blocked by PP2, FAK small interfering RNA (siRNA), caveolin-1 siRNA, or the caveolar disruptor methyl-β-cyclodextrin (MβCD). FN also increased phosphorylation of Akt and ERK 1/2, which were significantly blocked by either FAK siRNA, caveolin-1 siRNA, MβCD, GGTI-286 (RhoA inhibitor), or Y-27632 (Rho kinase inhibitor). FN-induced increase of protooncogenes (c-fos, c-myc, and c-Jun) and cell-cycle regulatory proteins (cyclin D1/CDK4 and cyclin E/CDK2) expression levels were attenuated by FAK siRNA or caveolin-1 siRNA. Furthermore, inhibition of each pathway such as integrin β1, Src, FAK, caveolin-1, RhoA, Akt, and ERK 1/2 blocked FN-induced [(3)H]-thymidine incorporation. We conclude that FN stimulates mouse ES cell proliferation via RhoA-PI3K/Akt-ERK 1/2 pathway through caveolin-1 phosphorylation.
authors.affiliation: Department of Veterinary Physiology, Biotherapy Human Resources Center (BK 21), College of Veterinary Medicine, Chonnam National University, Gwangju, Korea.
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Park
authors.forename: Jung Min
authors.initials: JM
authors.lastname: Ryu
authors.forename: Ho Jae
authors.initials: HJ
authors.lastname: Han
mesh_terms: D000818:Animals; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D005353:Fibronectins / Q000494:pharmacology; D051417:Focal Adhesion Kinase 1 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D051242:Caveolin 1; D005353:Fibronectins; D034741:RNA, Small Interfering; D019869:Phosphatidylinositol 3-Kinases; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D020742:rhoA GTP-Binding Protein