Download MendeleyCryo-EM structures of fungal and metazoan mitochondrial calcium uniporters.
Baradaran, R., Wang, C., Siliciano, A.F., Long, S.B.(2018) Nature 559: 580-584
- PubMed: 29995857
- DOI: https://doi.org/10.1038/s41586-018-0331-8
- Primary Citation of Related Structures:
6DNF - PubMed Abstract:
The 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 Å and 3.2 Å 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.
Organizational Affiliation:
Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
