Functions And Regulation Of ScRCH1in Saccharomyces Cerevisiae

Saccharomyces cerevisiae YMR034c, a human solute carrier family memberSLC10A7-related gene, is a functional homolog of Candida albicans CaRCH1, so we namedit as ScRCH1. The phenotype experiment shows that ScRCH1can partially complement thefunction of CaRCH1when transfromed pCR4-ScRCH1into Candida albicansCarch1/Carch1strains. In S. cerevisiae, deletion of ScRCH1compromises the calciumtolerance of the mutant lacking ScPMR1encoding the ER/Golgi calcium pump, indicatingPmr1and Rch1have genetic interaction in the regulation of calcium homeostasis. In contrast,deletion of ScRCH1does not affect the calcium sensitivity of cells lacking ScPMC1encodingthe vacuolar calcium pump. Further research the relationship of ScPMC1and ScRCH1isnecessary. ScRch1is induced by extracellular calcium stress and localizes to the plasmamembrane. Deletion mutation analysis indicates that the ninth C-terminal transmembranedomains of ScRch1is required for its function and subcellular localization. A functionalgenomic screen with mutants of223genes encoding transcription factors indicates thatmutation of six genes INO2, NGG1, ADA2, HAL9, CRZ1and SWI6, affects the transcriptionand localization of ScRch1. These genes are involved in the biosynthesis of phospholipid,histone acetylation and expression of ENA1encoding a Na+pump. The β-galactosidasereporter assay and promoter mutation analysis show that expression of ScRCH1is under thepositive control of Crz1p through the sole CDRE element in its promoter. These resultsprovide a basis for our understanding the regulation of calcium homeostasis by ScRch1inyeast cells.