Essential role of the NH2-terminal region of Cdc24 guanine nucleotide exchange factor in its initial polarized localization in Saccharomyces cerevisiae.

ABSTRACT: The cortical recruitment and accumulation of the small GTPase Cdc42 are crucial steps in the establishment of polarity, but this process remains obscure. Cdc24 is an upstream regulator of budding yeast Cdc42 that accelerates the exchange of GDP for GTP in Cdc42 via its Dbl homology (DH) domain. Here, we isolated five novel temperature-sensitive (ts) cdc24 mutants, the green fluorescent protein (GFP)-fused proteins of which lose their polarized localization at the nonpermissive temperature. All amino acid substitutions in the mutants were mapped to the NH2-terminal region of Cdc24, including the calponin homology (CH) domain. These Cdc24-ts mutant proteins did not interact with Bem1 at the COOH-terminal PB1 domain, suggesting a lack of exposure of the PB1 domain in the mutant proteins. The

SUBMITTER: Fujimura-Kamada K 

PROVIDER: S-EPMC3255939 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature