Abstract #86B

The role of actin during Golgi relocalization to the hyphal tip in C. albicans. Padmashree C. G. Rida, Akiko Nishikawa, Catherine A. Menzies, Gena Y. Won, Neta Dean. Biochemistry & Cell Biology, SUNY Stony Brook, Stony Brook, NY.
   In the pathogenic filamentous fungus Candida albicans the mechanism responsible for rapid, long range polarized secretion of proteins and cell wall components to the hyphal tip is not well understood. We have recently shown that during hyphal elongation in C. albicans, polarized secretion is accompanied by an actin-dependent relocalization of the Golgi from the cell body to the distal region of the hypha. Our data also suggest that actin filaments in C. albicans are involved in maintaining Golgi integrity during hyphal formation. Formins nucleate actin cable assembly and loss of the BNI1-enoded formin causes a hyphal-specific dispersal of the Golgi into a haze of finely dispersed vesicles. C. albicans bni1D null mutants display a secretion defect, causing an accumulation of acid phosphatase inside the cell, further implicating actin in maintaining Golgi function during hyphal formation. To further investigate the role of actin in mediating Golgi relocalization and integrity during hyphal formation, we are analyzing. C. albicans bni1 mutants that are specifically defective in actin nucleation, or that lead to the disruption of interactions with other proteins known to regulate Bni1p function. The phenotypic characterization of these bni1 mutants as well as other mutants that may affect Golgi movement will be presented.

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