Overexpression of Mdm36 reveals Num1 foci that mediate dynein-dependent microtubule sliding in budding yeast.

ABSTRACT: The current model for spindle positioning requires attachment of the microtubule (MT) motor cytoplasmic dynein to the cell cortex, where it generates pulling force on astral MTs to effect spindle displacement. How dynein is anchored by cortical attachment machinery to generate large spindle-pulling forces remains unclear. Here, we show that cortical clustering of Num1, the yeast dynein attachment molecule, is limited by its assembly factor Mdm36. Overexpression of Mdm36 results in an overall enhancement of Num1 clustering but reveals a population of dim Num1 clusters that mediate dynein anchoring at the cell cortex. Direct imaging shows that bud-localized, dim Num1 clusters containing around only six Num1 molecules mediate dynein-dependent spindle pulling via a lateral MT sliding mechanism

SUBMITTER: Omer S 

PROVIDER: S-EPMC7578358 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature