XKCM1: a Xenopus kinesin-related protein that regulates microtubule dynamics during mitotic spindle assembly.
We isolated a cDNA clone encoding a kinesin-related protein, which we named XKCM1. Antibodies to XKCM1 stain mitotic centromeres and spindle poles. Immunodepletion and antibody addition experiments in an in vitro spindle assembly assay show that XKCM1 is required for both establishment and maintenance of mitotic spindles. The structures that form in the absence of XKCM1 contain abnormally long microtubules. This long microtubule defect can be rescued by the addition of purified XKCM1 protein. Analysis of microtubule dynamics in a clarified mitotic extract reveals that loss of XKCM1 function causes a 4-fold suppression in the catastrophe frequency. XKCM1 thus exhibits a novel activity for a kinesin-related protein by promoting microtubule depolymerization during mitotic spindle assembly.
Department of Cellular and Molecular Pharmacology, University of California, San Francisco 94143-0450, USA.
C E
CE
Walczak
T J
TJ
Mitchison
A
A
Desai
D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D002457:Cell Extracts; D002503:Centromere / Q000502:physiology; D002875:Chromosomes / Q000502:physiology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression / Q000502:physiology; D015723:Gene Library; D016547:Kinesins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010063:Ovum / Q000166:cytology; D008941:Spindle Apparatus / Q000502:physiology*; D014981:Xenopus / Q000502:physiology*; D029867:Xenopus Proteins
D002457:Cell Extracts; D018076:DNA, Complementary; C088335:KIF11 protein, Xenopus; D008869:Microtubule-Associated Proteins; D029867:Xenopus Proteins; D016547:Kinesins