6X4S

MCU-EMRE complex of a metazoan mitochondrial calcium uniporter

Summary for 6X4S

• Entry DOI: 10.2210/pdb6x4s/pdb
• EMDB information: 22042
• Descriptor: Calcium uniporter protein,Protein EMRE homolog, mitochondrial-like Protein fusion, CALCIUM ION (2 entities in total)
• Functional Keywords: ion channel, calcium channel, mitochondrial calcium uniporter, mcu, emre, mitochondria, membrane protein
• Biological source: Tribolium castaneum (Red flour beetle); More
• Total number of polymer chains: 8
• Total formula weight: 220285.86

Authors

Long, S.B.,Wang, C.,Baradaran, R. (deposition date: 2020-05-22, release date: 2020-09-02, Last modification date: 2024-03-06)

Primary citation

Wang, C.,Baradaran, R.,Long, S.B.
Structure and Reconstitution of an MCU-EMRE Mitochondrial Ca 2+ Uniporter Complex.
J.Mol.Biol., 432:5632-5648, 2020

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 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.

PubMed: 32841658
DOI: 10.1016/j.jmb.2020.08.013

Experimental method

ELECTRON MICROSCOPY (3.5 Å)