Structural highlights
Publication Abstract from PubMedThe mitochondrial calcium uniporter (MCU) is a highly selective calcium channel and a major route of calcium entry into mitochondria. How the channel catalyses ion permeation and achieves ion selectivity are not well understood, partly because MCU is thought to have a distinct architecture in comparison to other cellular channels. Here we report cryo-electron microscopy reconstructions of MCU channels from zebrafish and Cyphellophora europaea at 8.5 A and 3.2 A resolutions, respectively. In contrast to a previous report of pentameric stoichiometry for MCU, both channels are tetramers. The atomic model of C. europaea MCU shows that a conserved WDXXEP signature sequence forms the selectivity filter, in which calcium ions are arranged in single file. Coiled-coil legs connect the pore to N-terminal domains in the mitochondrial matrix. In C. europaea MCU, the N-terminal domains assemble as a dimer of dimers; in zebrafish MCU, they form an asymmetric crescent. The structures define principles that underlie ion permeation and calcium selectivity in this unusual channel. Cryo-EM structures of fungal and metazoan mitochondrial calcium uniporters.,Baradaran R, Wang C, Siliciano AF, Long SB Nature. 2018 Jul 11. pii: 10.1038/s41586-018-0331-8. doi:, 10.1038/s41586-018-0331-8. PMID:29995857[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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