Starvation and temperature upshift cause an increase in the enzymatically active cell wall-associated glyceraldehyde-3-phosphate dehydrogenase protein in yeast

Abstract

The cell wall-associated glyceraldehyde-3-phosphate dehydrogenase (cwGAPDH) activity in Saccharomyces cerevisiae increases (two- to 10-fold, depending on the strain) in response to starvation and temperature upshift. Assays using transformants carrying pTDH, a yeast centromer derivative plasmid containing the Candida albicans TDH3 gene (encoding GAPDH) fused in frame with the yeast SUC2-coding region for internal invertase, showed that starvation and/or temperature upshift result in a similar increase in both cwGAPDH and cell wall-associated invertase activities. In addition, this incorporation of GAPDH protein into the cell wall in response to stress does not require (i) de novo protein synthesis, indicating that preexisting cytosolic enzyme is incorporated into the cell wall, (ii) nor the participation of the ubiquitin yeast stress response system, as no differences were observed between wild-type and polyubiquitin-depleted (Deltaubi4) strains.