| Title: | New regulators of a high affinity Ca2+ influx system revealed through a genome-wide screen in yeast |
| Author(s): | Martin DC; Kim H; Mackin NA; Maldonado-Baez L; Evangelista CC; Beaudry VG; Dudgeon DD; Naiman DQ; Erdman SE; Cunningham KW; |
| Address: | "Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA" |
| ISSN/ISBN: | 1083-351X (Electronic) 0021-9258 (Print) 0021-9258 (Linking) |
| Abstract: | "The bakers' yeast Saccharomyces cerevisiae utilizes a high affinity Ca(2+) influx system (HACS) to survive assaults by mating pheromones, tunicamycin, and azole-class antifungal agents. HACS consists of two known subunits, Cch1 and Mid1, that are homologous and analogous to the catalytic alpha-subunits and regulatory alpha2delta-subunits of mammalian voltage-gated calcium channels, respectively. To search for additional subunits and regulators of HACS, a collection of gene knock-out mutants was screened for abnormal uptake of Ca(2+) after exposure to mating pheromone or to tunicamycin. The screen revealed that Ecm7 is required for HACS function in most conditions. Cycloheximide chase experiments showed that Ecm7 was stabilized by Mid1, and Mid1 was stabilized by Cch1 in non-signaling conditions, suggesting they all interact. Ecm7 is a member of the PMP-22/EMP/MP20/Claudin superfamily of transmembrane proteins that includes gamma-subunits of voltage-gated calcium channels. Eleven additional members of this superfamily were identified in yeast, but none was required for HACS activity in response to the stimuli. Remarkably, many dozens of genes involved in vesicle-mediated trafficking and protein secretion were required to prevent spontaneous activation of HACS. Taken together, the findings suggest that HACS and calcineurin monitor performance of the membrane trafficking system in yeasts and coordinate compensatory processes. Conservation of this quality control system in Candida glabrata suggests that many pathogenic species of fungi may utilize HACS and calcineurin to resist azoles and other compounds that target membrane biosynthesis" |
| Keywords: | "Azoles/pharmacology Calcium/*metabolism Calcium Channels/genetics/*metabolism Candida/genetics/metabolism Cell Membrane/genetics/*metabolism Drug Resistance, Fungal/drug effects/physiology Genome-Wide Association Study/methods Ion Transport/drug effects/p;" |
| Notes: | "MedlineMartin, D Christian Kim, Hyemin Mackin, Nancy A Maldonado-Baez, Lymarie Evangelista, Carlos C Jr Beaudry, Veronica G Dudgeon, Drew D Naiman, Daniel Q Erdman, Scott E Cunningham, Kyle W eng R01 GM053082/GM/NIGMS NIH HHS/ R21 NS057023/NS/NINDS NIH HHS/ NS057023/NS/NINDS NIH HHS/ GM053082/GM/NIGMS NIH HHS/ Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S. 2011/01/22 J Biol Chem. 2011 Mar 25; 286(12):10744-54. doi: 10.1074/jbc.M110.177451. Epub 2011 Jan 20" |
