Regulation Of Mitochondrial ATPase Activity By Type 2C Protein Phosphatase In Saccharomyces Cerevisiae

Type 2C protein phosphatases (PP2C) are protein serine/threonine phosphatases. Until now, there are seven PP2C protein phosphatases identified in Saccharomyces cerevisiae, including Ptc1p, Ptc2p, Ptc3p, Ptc4p, Ptc5p, Ptc6p and Ptc7p. Ptc5p, Ptc6p and Ptc7p are present in mitochondria. Recent studies indicate that there are 80 phosphorylation sites in mitochondrial proteins and many of these sites are located in the subunits of mitochondrial ATP synthase. To investigate the regulation of PP2C on mitochondrial ATPase activity in yeast, we examined the activity of mitochondrion ATPase in deletion mutants of these PP2C genes. Our results indicate that the deletion of PTC1 can decrease the activity of ATPase activity, which correlates the growth defect of ptc1 mutant cells on YPD and YPA plate. In addition, the double deletion mutant of ptc1ptc5 and ptc1ptc7 demonstrate increased ATPase activities than the single ptc1 mutant and better growth phenotypes. In conclusion,PTC1 is involved in the regulation of mitochondrial ATP synthase activity, and both PTC5 and PTC7 interact genetically with PTC1 in the regulation of mitochondrial ATP synthase activity.