title: Glypican-1 regulates anaphase promoting complex/cyclosome substrates and cell cycle progression in endothelial cells.
abstract: Glypican-1 (GPC1), a member of the mammalian glypican family of heparan sulfate proteoglycans, is highly expressed in glioma blood vessel endothelial cells (ECs). In this study, we investigated the role of GPC1 in EC replication by manipulating GPC1 expression in cultured mouse brain ECs. Moderate GPC1 overexpression stimulates EC growth, but proliferation is significantly suppressed when GPC1 expression is either knocked down or the molecule is highly overexpressed. Flow cytometric and biochemical analyses show that high or low expression of GPC1 causes cell cycle arrest at mitosis or the G2 phase of the cell cycle, accompanied by endoreduplication and consequently polyploidization. We further show that GPC1 inhibits the anaphase-promoting complex/cyclosome (APC/C)-mediated degradation of mitotic cyclins and securin. High levels of GPC1 induce metaphase arrest and centrosome overproduction, alterations that are mimicked by overexpression of cyclin B1 and cyclin A, respectively. These observations suggest that GPC1 regulates EC cell cycle progression at least partially by modulating APC/C-mediated degradation of mitotic cyclins and securin.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI 53792, USA.
authors.forename: Dianhua
authors.initials: D
authors.lastname: Qiao
authors.forename: Xinhai
authors.initials: X
authors.lastname: Yang
authors.forename: Kristy
authors.initials: K
authors.lastname: Meyer
authors.forename: Andreas
authors.initials: A
authors.lastname: Friedl
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D001921:Brain / Q000098:blood supply / Q000378:metabolism; D002352:Carrier Proteins / Q000502:physiology*; D002453:Cell Cycle; D019925:Cyclin A / Q000378:metabolism; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D042783:Endothelial Cells / Q000378:metabolism*; D005434:Flow Cytometry / Q000379:methods; D053673:Glypicans / Q000096:biosynthesis / Q000502:physiology*; D051379:Mice; D008938:Mitosis; D008954:Models, Biological; D009389:Neovascularization, Pathologic; D064249:Securin; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C534700:Ccnb1 protein, mouse; D019925:Cyclin A; D019926:Cyclin B; D056744:Cyclin B1; D053673:Glypicans; D064249:Securin; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome