Molecular cloning of YlPMR1, a S-cerevisiae PMR1 homologue encoding a novel P-type secretory pathway CA2+-ATPase, in the yeast Yarrowia lipolytica

A novel P-type ATPase gene, Saccharomyces cerevisiae PMR1 homologue (YlPMR1), has been cloned and sequenced in the yeast, Yarrowia lipolytica. The putative gene product has 928 amino acids with a calculated molecular mass of 100 050 Da and a pI of 5.15. The deduced amino-acid sequence analysis demonstrated that the cloned gene product contains all 10 of the conserved regions in P-type ATPases and exhibits 55% amino-acid identity to the S. cerevisiae PMR1 gene product; however, it shows a relatively lower homology to PMCA (24%) and SERCA (33%), confirming the presence of a third class of Ca2+-ATPase (secretory pathway Ca2+-ATPase, SPCA). The YlPMR1-disrupted strain shows defective growth in low Ca2+ or EGTA-containing medium. In fact, a longer lag time (60 h) was observed in YlPMR1-defective mutant cells during cultivation in EGTA-containing YPD medium. These growth defects were overcome by adding Ca2+ and Mn2+ into the medium. Interestingly, whereas Mn2+ inhibits growth of the control strain, it significantly improves the growth of YlPMR1-disrupted cells. These results suggest an involvement of the YlPMR1 gene product in Ca2+ and Mn2+ ion homeostasis in Y. lipolytica. (C) 1997 Elsevier Science B.V.