Specialized sugar sensing in diverse fungi.

ABSTRACT: S. cerevisiae senses glucose and galactose differently. Glucose is detected through sensors that reside in the cellular plasma membrane. When activated, the sensors initiate a signal-transduction cascade that ultimately inactivates the Rgt1 transcriptional repressor by causing degradation of its corepressors Mth1 and Std1. This results in the expression of many HXT genes encoding glucose transporters. The ensuing flood of glucose into the cell activates Mig1, a transcriptional repressor that mediates "glucose repression" of many genes, including the GAL genes; hence, glucose sensing hinders galactose utilization. Galactose is sensed in the cytoplasm via Gal3. Upon binding galactose (and ATP), Gal3 sequesters the Gal80 protein, thereby emancipating the Gal4 transcriptional activator of the

SUBMITTER: Brown V 

PROVIDER: S-EPMC2762733 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature