The cortical protein Num1p is essential for dynein-dependent interactions of microtubules with the cortex.
In budding yeast, the mitotic spindle moves into the neck between the mother and bud via dynein-dependent sliding of cytoplasmic microtubules along the cortex of the bud. How dynein and microtubules interact with the cortex is unknown. We found that cells lacking Num1p failed to exhibit dynein-dependent microtubule sliding in the bud, resulting in defective mitotic spindle movement and nuclear segregation. Num1p localized to the bud cortex, and that localization was independent of microtubules, dynein, or dynactin. These data are consistent with Num1p being an essential element of the cortical attachment mechanism for dynein-dependent sliding of microtubules in the bud.
Heil-Chapdelaine
R A
RA
Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Oberle
J R
JR
Cooper
J A
JA
D000199:Actins / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002451:Cell Compartmentation; D020090:Chromosome Segregation; D003598:Cytoskeletal Proteins; D004398:Dyneins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D016547:Kinesins; D008853:Microscopy / Q000379:methods; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis / Q000235:genetics / Q000502:physiology*; D009068:Movement; D009687:Nuclear Proteins / Q000378:metabolism; D010641:Phenotype; D029701:Saccharomyces cerevisiae Proteins; D004718:Saccharomycetales; D008941:Spindle Apparatus / Q000378:metabolism*
D000199:Actins; D002135:Calcium-Binding Proteins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; C110443:KAR9 protein, S cerevisiae; C108256:KIP3 protein, S cerevisiae; D008869:Microtubule-Associated Proteins; C071961:NUM1 protein, S cerevisiae; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D004398:Dyneins; D016547:Kinesins