Localized secretion of acid phosphatase reflects the pattern of cell surface growth in Saccharomyces cerevisiae

Abstract

Secretion of cell wall-bound add phosphatase by Saccharomyces cerevisiae occurs along a restricted portion of the cell surface. Acid phosphatase activity produced during derepressed synthesis on a phosphate-limited growth medium is detected with an enzyme-specific stain and is localized initially to the bud portion of a dividing cell. After two to three generations of phosphate-limited growth, most of the cells can be stained; if further phosphatase synthesis is repressed by growth in excess phosphate, dividing cells are produced in which the parent but not the bud can be stained. Budding growth is interrupted in a-mating-type cells by a pheromone (α-factor) secreted by the opposite mating type; cell surface growth continues in the presence of a-factor and produces a characteristic cell tip. When acid phosphatase synthesis is initiated during a-factor treatment, only the cell tip can be stained; when phosphatase synthesis is repressed during a-factor treatment, the cell body but not the tip can be stained. A mixture of derepressed a cells and phosphatase-negative a cells form zygotes in which mainly one parent cell surface can be stained. The cell cycle mutant, cdc 24 (Hartwell, L. H. 1971. Exp. Cell Res. 69:265-276), fails to bud and, instead, expands symmetrically as a sphere at a nonpermissive temperature (37°C). This mutant does not form a cell tip during a-factor treatment at 37°C, and although acid phosphatase secretion occurs at this temperature, it is not localized. These results suggest that secretion reflects a polar mode of yeast cell-surface growth, and that this organization requires the cdc 24 gene product. © 1980, Rockefeller University Press., All rights reserved.