西亚试剂：Integrative genomics identifies MCU as an essential compone

Integrative genomics identifies MCU as an essential component of the mitochondrial calcium uniporter

Joshua M. Baughman, Fabiana Perocchi, Hany S. Girgis,Molly Plovanich,Casey A. Belcher-Timme, Yasemin Sancak, X. Robert Bao, Laura Strittmatter,Olga Goldberger, Roman L. Bogorad, Victor Koteliansky & Vamsi K. Mootha1

Mitochondria from diverse organisms are capable of transporting large amounts of Ca2+ via a ruthenium-red-sensitive, membrane-potential-dependent mechanism called the uniporter1, 2, 3, 4. Although the uniporter’s biophysical properties have been studied extensively, its molecular composition remains elusive. We recently used comparative proteomics to identify MICU1 (also known as CBARA1), an EF-hand-containing protein that serves as a putative regulator of the uniporter5. Here, we use whole-genome phylogenetic profiling, genome-wide RNA co-expression analysis and organelle-wide protein coexpression analysis to predict proteins functionally related to MICU1. All three methods converge on a novel predicted transmembrane protein, CCDC109A, that we now call ‘mitochondrial calcium uniporter’ (MCU). MCU forms oligomers in the mitochondrial inner membrane, physically interacts with MICU1, and resides within a large molecular weight complex. Silencing MCU in cultured cells or in vivo in mouse liver severely abrogates mitochondrial Ca2+ uptake, whereas mitochondrial respiration and membrane potential remain fully intact. MCU has two predicted transmembrane helices, which are separated by a highly conserved linker facing the intermembrane space. Acidic residues in this linker are required for its full activity. However, an S259A point mutation retains function but confers resistance to Ru360, the most potent inhibitor of the uniporter. Our genomic, physiological, biochemical and pharmacological data firmly establish MCU as an essential component of the mitochondrial Ca2+ uniporter.