Motile properties of the kinesin-related Cin8p spindle motor extracted from Saccharomyces cerevisiae cells

Larisa Gheber, Scot C. Kuo, M. Andrew Hoyt

Research output: Contribution to journalArticle

Abstract

We have developed microtubule binding and motility assays for Cin8p, a kinesin-related mitotic spindle motor protein from Saccharomyces cerevisiae. The methods examine Cin8p rapidly purified from crude yeast cell extracts. We created a recombinant form of CIN8 that fused the biotin carrying polypeptide from yeast pyrurate carboxylase to the carboxyl terminus of Cin8p. This form was biotinated in yeast cells and provided Cin8p activity in vivo. Avidin- coated glass surfaces were used to specifically bind biotinated Cin8p from crude extracts. Microtubules bound to the Cin8p-coated surfaces and moved at 3.4 ± 0.5 μm/min in the presence of ATP. Force production by Cin8p was directed toward the plus ends of microtubules. A mutation affecting the microtubule-binding site within the motor domain (cin8-F467A) decreased Cin8p's ability to bind microtubules to the glass surface by >10-fold, but reduced gliding velocity by only 35%. The cin8-3 mutant form, affecting the α2 helix of the motor domain, caused a moderate defect in microtubule binding, but motility was severely affected. cin8-F467A cells, but not cin8- 3 cells, were greatly impaired in bipolar spindle forming ability. We conclude that microtubule binding by Cin8p is more important than motility for proper spindle formation.

Original languageEnglish (US)
Pages (from-to)9564-9572
Number of pages9
JournalJournal of Biological Chemistry
Volume274
Issue number14
DOIs
StatePublished - Apr 2 1999

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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