8.A.45.1.6
EMRE regulatory subunit of CMU (TC# 1.A.77.1.17). MCU and EMRE form the minimal functional unit of the mitochondrial calcium uniporter complex in metazoans. Wang et al. 2020 functionally reconstituted an MCU-EMRE complex from the red flour beetle, Tribolium castaneum, and determined a cryo-EM structure of the complex at 3.5 Å resolution. They demonstrated robust Ca²⁺ uptake into proteoliposomes containing the purified complex. Uptake depended on EMRE and also on mitochondrial 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 TMS 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 (Wang et al. 2020).