Dynein and mast/orbit/CLASP have antagonistic roles in regulating kinetochore-microtubule plus-end dynamics.
Establishment and maintenance of the mitotic spindle requires the balanced activity of microtubule-associated proteins and motors. In this study we have addressed how the microtubule plus-end tracking protein mast/orbit/CLASP and cytoplasmic dynein regulate this process in Drosophila melanogaster embryos and S2 cells. We show that mast accumulates at kinetochores early in mitosis, which is followed by a poleward streaming upon microtubule attachment. This leads to a reduction of mast levels at kinetochores during metaphase and anaphase that depends largely on the microtubule minus end-directed motor cytoplasmic dynein. Surprisingly, we also found that co-depletion of dynein rescues spindle bipolarity in mast-depleted cells, while restoring normal microtubule poleward flux. Our results suggest that mast and dynein have antagonistic roles in the local regulation of microtubule plus-end dynamics at kinetochores, which are important for the maintenance of spindle bipolarity and normal spindle length.
Reis
Rita
R
IBMC Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
Feijão
Tália
T
Gouveia
Susana
S
Pereira
António J
AJ
Matos
Irina
I
Sampaio
Paula
P
Maiato
Helder
H
Sunkel
Claudio E
CE
D000818:Animals; D030801:Animals, Genetically Modified; D002460:Cell Line; D003595:Cytoplasmic Streaming; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D018386:Kinetochores / Q000378:metabolism*; D007814:Larva / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection
D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; C407307:chb protein, Drosophila; D004398:Dyneins