Biochemical properties of vacuolar zinc transport systems of Saccharomyces cerevisiae

The yeast vacuole plays an important role in zinc homeostasis by storing zinc for later use under deficient conditions, sequestering excess zinc for its detoxification, and buffering rapid changes in intracellular zinc levels. The mechanisms involved in vacuolar zinc sequestration are only poorly ch...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 2002-10, Vol.277 (42), p.39187-39194
Main Authors: MacDiarmid, Colin W, Milanick, Mark A, Eide, David J
Format: Article
Language:English
Subjects:
Adenosine Triphosphatases - metabolism
Adenosine Triphosphate - metabolism
Biological Transport
Calcium - metabolism
Cation Transport Proteins - metabolism
Cations
Cell Membrane - metabolism
Dose-Response Relationship, Drug
Electrophoresis, Polyacrylamide Gel
Fungal Proteins - metabolism
Hydrogen-Ion Concentration
Immunoblotting
Ions
Iron - metabolism
Kinetics
Manganese - metabolism
Membrane Transport Proteins
Mutation
Plasmids - metabolism
Saccharomyces cerevisiae - metabolism
Saccharomyces cerevisiae Proteins - metabolism
Time Factors
Vacuolar Proton-Translocating ATPases - metabolism
Vacuoles - metabolism
Zinc - metabolism
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The yeast vacuole plays an important role in zinc homeostasis by storing zinc for later use under deficient conditions, sequestering excess zinc for its detoxification, and buffering rapid changes in intracellular zinc levels. The mechanisms involved in vacuolar zinc sequestration are only poorly characterized. Here we describe the properties of zinc transport systems in yeast vacuolar membrane vesicles. The major zinc transport activities in these vesicles were ATP-dependent, requiring a H+ gradient generated by the V-ATPase for function. One system we identified was dependent on the ZRC1 gene, which encodes a member of the cation diffusion facilitator family of metal transporters. These data are consistent with the proposed role of Zrc1 as a vacuolar zinc transporter. Zrc1-independent activity was also observed that was not dependent on the closely related vacuolar Cot1 protein. Both Zrc1-dependent and independent activities showed a high specificity for Zn(2+) over other physiologically relevant substrates such as Ca2+, Fe2+, and Mn2+. Moreover, these systems had high affinities for zinc with apparent K(m) values in the 100-200 nm range. These results provide biochemical insight into the important role of Zrc1 and related proteins in eukaryotic zinc homeostasis.
ISSN:0021-9258
DOI:10.1074/jbc.M205052200