Molecular mechanisms of kinetochore capture by spindle microtubules.
For high-fidelity chromosome segregation, kinetochores must be properly captured by spindle microtubules, but the mechanisms underlying initial kinetochore capture have remained elusive. Here we visualized individual kinetochore-microtubule interactions in Saccharomyces cerevisiae by regulating the activity of a centromere. Kinetochores are captured by the side of microtubules extending from spindle poles, and are subsequently transported poleward along them. The microtubule extension from spindle poles requires microtubule plus-end-tracking proteins and the Ran GDP/GTP exchange factor. Distinct kinetochore components are used for kinetochore capture by microtubules and for ensuring subsequent sister kinetochore bi-orientation on the spindle. Kar3, a kinesin-14 family member, is one of the regulators that promote transport of captured kinetochores along microtubules. During such transport, kinetochores ensure that they do not slide off their associated microtubules by facilitating the conversion of microtubule dynamics from shrinkage to growth at the plus ends. This conversion is promoted by the transport of Stu2 from the captured kinetochores to the plus ends of microtubules.
Tanaka
Kozo
K
School of Life Sciences, University of Dundee, Wellcome Trust Biocentre, Dundee DD1 5EH, UK.
Mukae
Naomi
N
Dewar
Hilary
H
van Breugel
Mark
M
James
Euan K
EK
Prescott
Alan R
AR
Antony
Claude
C
Tanaka
Tomoyuki U
TU
D001692:Biological Transport; D002453:Cell Cycle; D020090:Chromosome Segregation; D015825:Chromosomes, Fungal / Q000378:metabolism* / Q000648:ultrastructure; D016547:Kinesins / Q000378:metabolism; D018386:Kinetochores / Q000378:metabolism* / Q000648:ultrastructure; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D020931:ran GTP-Binding Protein / Q000378:metabolism
C063504:KAR3 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; C109414:STU2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D016547:Kinesins; D020931:ran GTP-Binding Protein