Phosphorylation by p34cdc2 regulates spindle association of human Eg5, a kinesin-related motor essential for bipolar spindle formation in vivo

Cell. 1995 Dec 29;83(7):1159-69. doi: 10.1016/0092-8674(95)90142-6.

Abstract

We have isolated a human homolog of Xenopus Eg5, a kinesin-related motor protein implicated in the assembly and dynamics of the mitotic spindle. We report that microinjection of antibodies against human Eg5 (HsEg5) blocks centrosome migration and causes HeLa cells to arrest in mitosis with monoastral microtubule arrays. Furthermore, an evolutionarily conserved cdc2 phosphorylation site (Thr-927) in HsEg5 is phosphorylated specifically during mitosis in HeLa cells and by p34cdc2/cyclin B in vitro. Mutation of Thr-927 to nonphosphorylatable residues prevents HsEg5 from binding to centrosomes, indicating that phosphorylation controls the association of this motor with the spindle apparatus. These results indicate that HsEg5 is required for establishing a bipolar spindle and that p34cdc2 protein kinase directly regulates its localization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antibody Specificity
  • Base Sequence
  • CDC2 Protein Kinase / metabolism*
  • HeLa Cells / cytology
  • Humans
  • Kinesin / metabolism*
  • Microinjections
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / immunology
  • Microtubule-Associated Proteins / metabolism*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Phosphorylation / drug effects
  • Spindle Apparatus / physiology*
  • Threonine / genetics
  • Xenopus Proteins*

Substances

  • KIF11 protein, Xenopus
  • Microtubule-Associated Proteins
  • Xenopus Proteins
  • Threonine
  • CDC2 Protein Kinase
  • Kinesin

Associated data

  • GENBANK/X85137