Involvement of the cytoskeleton in the intracellular distribution of mannoproteins in hyphal cells of Candida albicans

Cylindrical growth of fungal hyphae requires spatial organization of secret ion to the growing tip. In order to better understand the involvement of th e cytoskeleton in the spatial control of the secretion, we examined the eff ects of two anti-cytoskeletal drugs, benomyl and cytochalasin A, on the int racellular distribution of mannoproteins, a major secreted component of the cell wall, in hyphal cells of the dimorphic yeast Candida albicans. The di stribution of the mannoproteins was assessed by epifluorescence microscopy with a fluorescence-labelled lentil lectin (FTTC-LCA). Brefeldin A, an inhi bitor of secretory transport, induced a localized accumulation of the manno polysaccharides near the tip as previously reported (Akashi et al, 1997). B enomyl, an inhibitor of microtubules, disrupted the localized accumulation of the polysaccharides, Cytochalasin A, an inhibitor of actin, caused a loc alized accumulation of the polysaccharides near the tip, where Golgi-like c isternae were also accumulated. Both cytochalasin A and brefeldin A caused some modifications of the actin network, but neither disturbed the polariza tion of actin and neither affected the microtubule network. Our results sug gested that the microtubules are involved in membrane trafficking in hyphal growth as well as the cell polarity of the hyphae.