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

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• 作者：Toshihiko Cho ; Aya Ishii-Kato ; Yuko Fukata ; Yoshitaka Nakayama ; Kazuko Iida ; Masaki Fukata and Hidetoshi Iida
• 刊名：Genes to Cells
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：22
• 期：1
• 页码：94-104
• 全文大小：643K
• ISSN：1365-2443

文摘

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.