title: The TOGp protein is a new human microtubule-associated protein homologous to the Xenopus XMAP215.
abstract: We have recently identified a 6,449 bp cDNA, termed colonic, hepatic tumor over-expressed gene (ch-TOG), that is highly expressed in human tumors and brain. Its single open reading frame encodes a putative 218,000 Da polypeptide, TOGp. Antibodies generated against a bacterially expressed TOGp fragment specifically recognize a 218, 000 Da polypeptide in two human cell lines and in brain. Immunofluorescence microscopy using affinity-purified TOGp antibodies revealed that the distribution of TOGp was dependent upon the cell cycle. During interphase, TOGp was found concentrated in the perinuclear cytoplasm, where it co-localized with ER markers. In contrast anti-TOGp antibodies stained centrosomes and spindles in mitotic cells. TOGp co-sedimented with taxol-stabilized microtubules in vitro. Moreover, a TOGp enriched fraction promotes microtubule assembly both in solution and from nucleation centers. Finally, sequence comparison and immunologic cross-reaction suggest that TOGp is homologous to XMAP215, a previously described microtubule associated protein (MAP) from Xenopus eggs. These results suggest that TOGp is a MAP and that TOGp/XMAP215 may be necessary for microtubules rearrangements and spindle assembly in rapidly dividing cells.
authors.affiliation: INSERM Unite 128, 34293 Montpellier, France.
authors.forename: S
authors.initials: S
authors.lastname: Charrasse
authors.forename: M
authors.initials: M
authors.lastname: Schroeder
authors.forename: C
authors.initials: C
authors.lastname: Gauthier-Rouviere
authors.forename: F
authors.initials: F
authors.lastname: Ango
authors.forename: L
authors.initials: L
authors.lastname: Cassimeris
authors.forename: D L
authors.initials: DL
authors.lastname: Gard
authors.forename: C
authors.initials: C
authors.lastname: Larroque
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D003429:Cross Reactions; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006801:Humans; D007399:Interphase / Q000502:physiology; D008861:Microsomes / Q000737:chemistry; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus / Q000378:metabolism; D013347:Subcellular Fractions / Q000737:chemistry; D029867:Xenopus Proteins; D014982:Xenopus laevis
chemical_list: C486738:CKAP5 protein, Xenopus; C454180:CKAP5 protein, human; D008869:Microtubule-Associated Proteins; D029867:Xenopus Proteins