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Title | Structure and Reconstitution of an MCU-EMRE Mitochondrial Ca Uniporter Complex. |
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Journal, issue, pages | J Mol Biol, Vol. 432, Issue 20, Page 5632-5648, Year 2020 |
Publish date | Sep 18, 2020 |
Authors | Chongyuan Wang / Rozbeh Baradaran / Stephen Barstow Long / |
PubMed Abstract | The proteins MCU and EMRE form the minimal functional unit of the mitochondrial calcium uniporter complex in metazoans, a highly selective and tightly controlled Ca channel of the inner mitochondrial ...The proteins MCU and EMRE form the minimal functional unit of the mitochondrial calcium uniporter complex in metazoans, a highly selective and tightly controlled Ca channel of the inner mitochondrial membrane that regulates cellular metabolism. Here we present functional reconstitution of an MCU-EMRE complex from the red flour beetle, Tribolium castaneum, and a cryo-EM structure of the complex at 3.5 Å resolution. Using a novel assay, we demonstrate robust Ca uptake into proteoliposomes containing the purified complex. Uptake is dependent on EMRE and also on the mitochondrial lipid cardiolipin. The structure reveals a tetrameric channel with a single ion pore. EMRE is located at the periphery of the transmembrane domain and associates primarily with the first transmembrane helix of MCU. Coiled-coil and juxtamembrane domains within the matrix portion of the complex adopt markedly different conformations than in a structure of a human MCU-EMRE complex, suggesting that the structures represent different conformations of these functionally similar metazoan channels. |
External links | J Mol Biol / PubMed:32841658 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.5 Å |
Structure data | EMDB-22042, PDB-6x4s: |
Chemicals | ChemComp-CA: |
Source |
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Keywords | MEMBRANE PROTEIN / ion channel / calcium channel / mitochondrial calcium uniporter / MCU / EMRE / mitochondria |