Role of actin-bundling protein Sac6 in growth of Cryptococcus neoformans at low oxygen concentration.
Abstract
Cryptococcus neoformans, the etiologic agent of cryptococcosis, is an obligately aerobic yeast that inhabits an environmental niche exposed to ambient air. The cell doubling time was significantly prolonged under 1% O(2) relative to that under normoxic conditions. No apparent cell cycle arrest occurred following a shift from ambient air to 1% O(2). However, yeast cells became hypersensitive to the actin monomer-sequestering agent latrunculin A at 1% O(2), indicating that proper actin function is critical for growth at low oxygen concentrations. We showed that Sac6, an actin-binding protein, played an important role in cell growth under low oxygen conditions. Sac6 colocalized with cortical actin patches and with the ring structures between mother cells and buds. Under low oxygen conditions, the sac6 deletion mutant grew poorly, and accumulation of the actin capping protein Cap1 was observed in the vacuole of the sac6Δ strain. Furthermore, endocytic processes were hampered in the sac6Δ mutant, but cell polarity and cytokinesis were not visibly disturbed. The deficiency of endocytosis in the sac6Δ strain could be rescued by 1 M sorbitol under 1% O(2), but growth remained retarded. These results suggest an absence of a direct link ...Continue Reading
References
Genetic analysis of the bipolar pattern of bud site selection in the yeast Saccharomyces cerevisiae.
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Actin-binding Proteins
Actin-binding proteins are a component of the actin cytoskeleton that play essential roles in cellular functions such as regulation of actin polymerization, maintenance of cell polarity, gene expression regulation, cell motility and many more functions. Discover the latest research on actin-binding proteins here.