The N- and C-terminal mutations in tryptophan permease Tat2 confer cell growth in Saccharomyces cerevisiae under high-pressure and low-temperature conditions

Abstract

Tryptophan uptake appears to be the limiting factor in growth of tryptophan auxotrophic Saccharomyces cerevisiae strains under the conditions of high hydrostatic pressure and low temperature. When the cells are subjected to a pressure of 25 MPa, tryptophan permease Tat2 is degraded in a manner dependent on ubiquitination by Rsp5. One of the high-pressure growth-conferring genes, HPG2, was shown to be allelic to TAT2. The HPG2-1 (Tat2(E27F)) mutation site is located within the ExKS motif in the N-terminus, and the HPG2-2 (Tat2(D563N)) and HPG2-3 (Tat2(E570K)) mutation sites are located at the KQEIAE sequence in the C-terminus. The HPG2 mutations enhance the stability of Tat2 during high-pressure or low-temperature incubation, leading to cell growth under these stressful conditions. These results suggest that the cytoplasmic tails are involved in Rsp5-mediated ubiquitination of Tat2 under high-pressure or low-temperature conditions.

Phospholipid Flippases Lem3p-Dnf1p and Lem3p-Dnf2p Are Involved in the Sorting of the Tryptophan Permease Tat2p in Yeast

“…8D), consistent with the previous observation that the mutated lysine residues are ubiquitin acceptor sites; this protein would be continuously transported to the plasma membrane from the TGN and would be defective in its endocytosis (22,65). In fact, Tat2p 5KϾA was exclusively found in the PM-rich fraction (Fig.…”

Glycosylphosphatidylinositol-anchored Proteins Are Required for the Transport of Detergent-resistant Microdomain-associated Membrane Proteins Tat2p and Fur4p

“…This indicates that a loss of Tat2p function in gwt1-10 cells is due to its mislocalization. Because Tat2p is required for cell growth at a low temperature (15°C) (53,54), it is quite conceivable that the Cs Ϫ phenotype of gwt1-10 cells is caused by the reduced uptake of tryptophan due to the mislocalization of Tat2p. If Tat2p is accumulated entirely in the ER, it is unexpected that the Cs Ϫ phenotype of gwt1-10 cells is suppressed by the BUL1 deletion.…”

Exploration of the Effects of High Hydrostatic Pressure on Microbial Growth, Physiology and Survival: Perspectives from Piezophysiology

“…Another high-pressure growth gene, HPG2, is allelic to TAT2. 85) When yeast cells are treated with rapamycin, an immunosuppressive agent, or are starved of nutrients, degradation of Tat2 is initiated by covalent binding of ubiquitin molecules to the 29th and/or 31st lysine at the N-terminal tail of the Tat2 protein. 88) The HPG2 mutation sites are located in the regulatory domains of the N-and C-terminal tails of the Tat2 protein.…”

“…88) The HPG2 mutation sites are located in the regulatory domains of the N-and C-terminal tails of the Tat2 protein. 85) The amino acid substitutions are likely to interfere with ubiquitination on the 29th and/or 31st lysine by Rsp5 ubiquitin ligase. Consequently, the mutant forms of Tat2 are stabilized, leading to highpressure growth of HPG2 cells.…”