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  • Tubulin isotypes optimize distinct spindle positioning mechanisms during yeast mitosis. The Journal of cell biology Nsamba, E. T., Bera, A., Costanzo, M., Boone, C., Gupta, M. L. 2021; 220 (12)

    Abstract

    Microtubules are dynamic cytoskeleton filaments that are essential for a wide range of cellular processes. They are polymerized from tubulin, a heterodimer of alpha- and beta-subunits. Most eukaryotic organisms express multiple isotypes of alpha- and beta-tubulin, yet their functional relevance in any organism remains largely obscure. The two alpha-tubulin isotypes in budding yeast, Tub1 and Tub3, are proposed to be functionally interchangeable, yet their individual functions have not been rigorously interrogated. Here, we develop otherwise isogenic yeast strains expressing single tubulin isotypes at levels comparable to total tubulin in WT cells. Using genome-wide screening, we uncover unique interactions between the isotypes and the two major mitotic spindle positioning mechanisms. We further exploit these cells to demonstrate that Tub1 and Tub3 optimize spindle positioning by differentially recruiting key components of the Dyn1- and Kar9-dependent mechanisms, respectively. Our results provide novel mechanistic insights into how tubulin isotypes allow highly conserved microtubules to function in diverse cellular processes.

    View details for DOI 10.1083/jcb.202010155

    View details for PubMedID 34739032