title: Cell cycle-dependent phosphorylation of centrosomes: localization of phosphopeptide specific antibodies to the centrosome.
abstract: The microtubule nucleation capacity of the centrosome increases dramatically as cells progress from interphase into mitosis. The increase in nucleation capacity of the centrosome correlates with the cell cycle-dependent localization of the mitotic protein monoclonal-2 (MPM-2) phosphoepitope-specific antibody to the mitotic centrosome. Therefore, the phosphorylation state of centrosomal components may regulate the microtubule nucleation capacity of this organelle during mitosis. Neither the identity of the MPM-2 kinase(s) nor all of the MPM-2-reactive phosphoproteins associated with the centrosome have been fully elucidated. Only recently have the characteristics of the MPM-2 epitope site been defined, and we used this information to prepare polyclonal antibodies against synthetic phosphopeptides containing potential MPM-2 epitopes derived from the sequences of two MPM-2-reactive proteins, topoisomerase II, and microtubule associated protein 1B (MAP1B). We demonstrate that these phosphopeptide-specific antibodies also localize to the centrosome in a cell cycle-dependent fashion. Thus, polyclonal antibodies have been generated against defined phosphopeptides that reiterate many of the immunofluorescence staining properties exhibited by the MPM-2 antibody. These new phosphopeptide-specific antibodies will provide additional probes to examine the phosphorylation of centrosomal components and the functional consequences of their phosphorylation during mitosis.
authors.affiliation: Department of Physiology and Cell Biology, The Ohio State University, Columbus 43210, USA.
authors.forename: D D
authors.initials: DD
authors.lastname: Vandré
authors.forename: Y
authors.initials: Y
authors.lastname: Feng
authors.forename: M
authors.initials: M
authors.lastname: Ding
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D016466:CHO Cells; D002453:Cell Cycle / Q000502:physiology*; D002460:Cell Line; D018385:Centrosome / Q000737:chemistry / Q000502:physiology*; D006224:Cricetinae; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D007106:Immune Sera; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology; D008938:Mitosis; D010748:Phosphopeptides / Q000235:genetics / Q000276:immunology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000276:immunology; D008941:Spindle Apparatus / Q000502:physiology; D014407:Tumor Cells, Cultured
chemical_list: D000906:Antibodies; D000939:Epitopes; D007106:Immune Sera; D008869:Microtubule-Associated Proteins; D010748:Phosphopeptides; C085284:microtubule-associated protein 1B; D017346:Protein Serine-Threonine Kinases