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The single-pass Essential MCU REgulator membrane protein with aspartate-rich tail of 107 aas, EMRE or MICU1/2 (Sancak et al. 2013).  Also called the chromosome 22 ORF32 protein.  Functions to interlink MICU1 and 2 to MCU in the mitorchondrial uniporter complex (TC# 1.A.77 (Vais et al. 2020). In amoeba and fungi, MCU homologs are sufficient to form a functional calcium channel, whereas human MCU exhibits a strict requirement for EMRE for conductance.  EMRE directly interacts with human MCU at its transmembrane domains as well as the 10 aa interaction domain (MacEwen et al. 2020). EMRE stabilizes the EDD of MCU, permitting both channel opening and calcium conductance, consistent with recently published structures of MCU-EMRE (MacEwen et al. 2020). See the family description of MCU (1.A.77) for more deetails.

Metazoa, Chordata
EMRE of Homo sapiens

Mitochondrial portein SMDT1 homologue

Metazoa, Arthropoda
SMDT1 homologue of Drosophila melanogaster

Tag-299 protein of 90 aas

Metazoa, Nematoda
Tag-299 as Caenorhabditis elegans

EMRE homologue of 91 aas

Metazoa, Echinodermata
EMRE homologue of Strongylocentrotus purpuratus (Purple sea urchin)

Uncharacterized protein of 81 aas

UP of Capsaspora owczarzaki

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).

Metazoa, Arthropoda
EMRE of Tribolium castaneum

Uncharacterized protein of 163 aas.

UP of Monosiga brevicollis

Uncharacterized protein of 89 aas

UP of Salpingoeca rosetta