RT Journal Article SR Electronic T1 The TOGp protein is a new human microtubule-associated protein homologous to the Xenopus XMAP215 JF Journal of Cell Science JO J. Cell Sci. FD The Company of Biologists Ltd SP 1371 OP 1383 VO 111 IS 10 A1 Charrasse, S. A1 Schroeder, M. A1 Gauthier-Rouviere, C. A1 Ango, F. A1 Cassimeris, L. A1 Gard, D.L. A1 Larroque, C. YR 1998 UL http://jcs.biologists.org/content/111/10/1371.abstract AB 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.