Cell Biology

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Science  23 Apr 2004:
Vol. 304, Issue 5670, pp. 491
DOI: 10.1126/science.304.5670.491d

Budding yeast cells can divide asexually or, under some conditions, they can mate with other yeast cells. Mating is a process in which a yeast cell orients its growth toward a prospective partner up a pheromone gradient and sends out a mating projection (shmoo) in order to initiate contact and cell-cell fusion. This process relies on the actin cytoskeleton for directional growth, and the formin homolog Bni1p participates by facilitating the assembly of cortical actin cables. Matheos et al. show that a component of a previously described signaling cascade, the pheromone-activated kinase Fus3p, can also phosphorylate Bni1p, and that this is required for successful reorientation of growth during mating. Mutant yeast cells that lack Fus3p suffer defects in actin and cell polarization (similar to those in cells lacking Bni1p), and Bni1p fails to localize appropriately to the cell cortex. In these cells, overexpression of Bni1p suppresses these defects, restoring actin assembly, cell polarization, and mating. — SMH

J. Cell Biol. 165, 99 (2004).

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