The Cortical Protein Num1p Is Essential for Dynein-Dependent Interactions of Microtubules with the Cortex

• Published in: The Journal of cell biology Vol. 151; no. 6; pp. 1337 - 1343
• Main Authors: Heil-Chapdelaine, Richard A., Oberle, Jessica R., Cooper, John A.
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 11.12.2000; The Rockefeller University Press
• Subjects: Actins; Actins - metabolism; Calcium-Binding Proteins - metabolism; Cell Compartmentation; Cell cycle; Cell division; Cells; Cellular biology; Chromosome Segregation; Cytokines; Cytoskeletal Proteins; Daughter cells; Dyneins - metabolism; Fluorescence; Fungal Proteins - metabolism; Kinesin; Microscopy - methods; Microtubule-Associated Proteins - metabolism; Microtubules; Microtubules - metabolism; Mitosis - genetics; Mitosis - physiology; Mitotic spindle apparatus; Mother cells; Movement; Nuclear Proteins - metabolism; Num1 protein; Phenotype; Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Saccharomycetales; Spindle Apparatus - metabolism; Yeasts
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.151.6.1337

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.