Kinesin-related proteins required for structural integrity of the mitotic spindle.
For S. cerevisiae cells, the assembly of a bipolar mitotic spindle requires the action of either Cin8p or Kip1p, gene products related to the mechanochemical enzyme kinesin. In this paper we demonstrate that the activity of either one of these proteins is also required following spindle assembly. When their function was eliminated, preanaphase bipolar spindles rapidly collapsed, with previously separated poles being drawn together. In contrast, anaphase spindles were apparently resistant to collapse. Deletion of kinesin-related KAR3 partially suppressed the phenotypes associated with loss of Cin8p/Kip1p function. Our findings suggest that the structure of the preanaphase bipolar spindle is maintained by counteracting forces produced by kinesin-related proteins.
Saunders
W S
WS
Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.
Hoyt
M A
MA
D000705:Anaphase; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D016547:Kinesins; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000502:physiology*; D020409:Molecular Motor Proteins; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins; D008941:Spindle Apparatus / Q000502:physiology* / Q000648:ultrastructure
C075342:CIN8 protein, S cerevisiae; D005656:Fungal Proteins; C063504:KAR3 protein, S cerevisiae; C431747:KIP1 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; D020409:Molecular Motor Proteins; D029701:Saccharomyces cerevisiae Proteins; D016547:Kinesins