The BioGRID | PUBLICATION VIEW

	Jun (2007); 0:
Identification and characterization of Vnx1p, a novel type of vacuolar monovalent cation-H- antiporter of Saccharomyces cerevisiae-
Cagnac O, Leterrier M, Yeager M, Blumwald E
Dept of Plant Sciences - Mail Stop 5, University of California, Davis, CA 95616-
Abstract: We identified and characterized Vnx1p, a novel vacuolar monovalent cation-H- antiporter encoded by the ORF YNL321w from Saccharomyces cerevisiae- In spite of the homology of Vnx1p with other members of the CAX -Calcium eXanger- family of transporters, Vnx1p is unable to mediate Ca2- transport but is a low affinity Na--H- and K--H- antiporter with a Km of 22-4 mM and 82-2 mM for Na- and K-, respectively- Sequence analyses of Vnx1p revealed the absence of key amino acids shown to be essential for Ca2--H- exchange- vnx1 cells displayed growth inhibition when grown in the presence of hygromycin B or NaCl- Vnx1p activity was found in the vacuoles and shown to be dependent on the electrochemical potential gradient of H- generated by the action of the V-type H--ATPase- The presence of Vnx1p at the vacuolar membrane was further confirmed with cells expressing a VNX1--GFP chimeric gene- Similar to Nhx1p, the prevacuolar compartment-bound Na--H- antiporter, the vacuole-bound Vnx1p appears to play roles in the regulation of ion homeostasis and cellular pH-
[PUBMED: 17588950]