title: Identification of a protein that interacts with tubulin dimers and increases the catastrophe rate of microtubules.
abstract: Using a polymerization inhibition assay, we have purified a small, heat stable protein that physically interacts with tubulin dimers and increases the catastrophe rate of microtubules. Sequence analysis identified this protein as oncoprotein 18 (Op18)/stathmin, a conserved phosphoprotein that is highly expressed in leukemia cells. Immunodepletion experiments in Xenopus egg extracts showed that Op18/stathmin is involved in physiological regulation of mitotic microtubule dynamics. Op18/stathmin is a microtubule regulator that preferentially interacts with unpolymerized subunits. It is a candidate for increasing the microtubule catastrophe rate in mitosis and might also regulate microtubule dynamics in response to external signals.
authors.affiliation: Department of Biochemistry, University of California, San Francisco, 94143-0448, USA.
authors.forename: L D
authors.initials: LD
authors.lastname: Belmont
authors.forename: T J
authors.initials: TJ
authors.lastname: Mitchison
mesh_terms: D000818:Animals; D002417:Cattle; D008868:Microtubule Proteins / Q000302:isolation & purification; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D010750:Phosphoproteins / Q000032:analysis*; D050777:Stathmin; D013950:Thymus Gland / Q000166:cytology; D014020:Tissue Extracts / Q000737:chemistry; D014404:Tubulin / Q000378:metabolism*; D014981:Xenopus; D029867:Xenopus Proteins
chemical_list: D008868:Microtubule Proteins; D010750:Phosphoproteins; C493996:STMN1 protein, Xenopus; D050777:Stathmin; D014020:Tissue Extracts; D014404:Tubulin; D029867:Xenopus Proteins