Analysis of Mutations in the Pma1 Plasma Membrane Atpase Proton Pump That Suppress a Temperature Sensitive Growth Defect Phenotype Of Vacuolar Membrane Atpase Proton Pump Deficient Saccharomyces Cerevisiae



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The P-type proton pump, Pma1p and the vacuolar H+-ATPase (V-ATPase) proton pump play significant roles in balancing pH homeostasis in eukaryotic cells. In budding yeast, the PMA1 gene is critical for yeast survival, whereas mutations compromising V-ATPase activity cause conditional lethality. The yeast VMA21 gene encodes for the chaperone protein Vma21 that is required for complete assembly of the multisubunit V-ATPase complex. The loss of vacuolar acidity due to deficiency of V-ATPase activity has been linked to disrupted growth phenotypes. Yeast vma21 deficient mutants exhibit sensitivity to cold temperatures, CaCl2 and acetic acid. This sensitivity can be suppressed by a Pma1-G158S mutation suggesting an interdependence between Pma1p and the V-ATPase. In this study, we address how Pma1-G158S mutation affects wildtype and V-ATPase deficient cells in response to changes in extracellular conditions. Using CRISPR/Cas9 gene editing technology, we performed site-directed mutagenesis of G158 in an attempt to analyze structure-function relationships at this amino acid position. Our observations suggest that mutations at this position may regulate aging phenotype and cellular dysfunctions in yeast Saccharomyces cerevisiae and multicellular eukaryotes.



DNA damage, Vacuolar acidity, Saccharomyces cerevisiae, Proton pump, Vacuolar ATPase, pH homeostasis