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Genes Cells. 2017 Jan;22(1):94-104. doi: 10.1111/gtc.12458. Epub 2016 Dec 9.

Coupling of a voltage-gated Ca2+ channel homologue with a plasma membrane H+ -ATPase in yeast.

Author information

1
Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei-shi, Tokyo, 184-8501, Japan.
2
Division of Membrane Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, 444-8787, Japan.
3
Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, 444-8787, Japan.
4
Laboratory of Biomembrane, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, 156-8506, Japan.

Abstract

Yeast has a homologue of mammalian voltage-gated Ca2+ channels (VGCCs), enabling the efficient uptake of Ca2+ . It comprises two indispensable subunits, Cch1 and Mid1, equivalent to the mammalian pore-forming α1 and auxiliary α2 /δ subunits, respectively. Unlike the physiological roles of Cch1/Mid1 channels, the regulatory mechanisms of the yeast VGCC homologue remain unclear. Therefore, we screened candidate proteins that interact with Mid1 by an unbiased proteomic approach and identified a plasma membrane H+ -ATPase, Pma1, as a candidate. Mid1 coimmunoprecipitated with Pma1, and Mid1-EGFP colocalized with Pma1-mCherry at the plasma membrane. The physiological relevance of their interaction was determined using the temperature-sensitive mutant, pma1-10. At the nonpermissive temperature, the membrane potential was less negative and Ca2+ uptake was lower in pma1-10 than in wild-type cells. Increased extracellular H+ increased the rate of Ca2+ uptake. Therefore, H+ extrusion by Pma1 may be important for Ca2+ influx through Cch1/Mid1. These results suggest that Pma1 interacts physically with Cch1/Mid1 Ca2+ channels to enhance their activity via its H+ -pumping activity.

PMID:
27935186
DOI:
10.1111/gtc.12458
[Indexed for MEDLINE]
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