MCU encodes the pore conducting mitochondrial calcium currents

Abstract

Mitochondrial calcium (Ca2+) import is a well-described phenomenon regulating cell survival and ATP production. Of multiple pathways allowing such entry, the mitochondrial Ca2+ uniporter is a highly Ca2+-selective channel complex encoded by several recently-discovered genes. However, the identity of the pore-forming subunit remains to be established, since knockdown of all the candidate uniporter genes inhibit Ca2+ uptake in imaging assays, and reconstitution experiments have been equivocal. To definitively identify the channel, we use whole-mitoplast voltage-clamping, the technique that originally established the uniporter as a Ca2+ channel. We show that RNAi-mediated knockdown of the mitochondrial calcium uniporter (MCU) gene reduces mitochondrial Ca2+ current (IMiCa), whereas overexpression increases it. Additionally, a classic feature of IMiCa, its sensitivity to ruthenium red inhibition, can be abolished by a point mutation in the putative pore domain without altering current magnitude. These analyses establish that MCU encodes the pore-forming subunit of the uniporter channel.DOI: http://dx.doi.org/10.7554/eLife.00704.001

Adrenergic Signaling Regulates Mitochondrial Ca2+ Uptake Through Pyk2-Dependent Tyrosine Phosphorylation of the Mitochondrial Ca2+ Uniporter

“…This evidence strongly supports the hypothesis that Pyk2-mediated MCU oligomerization is directly linked to an increase in mitochondrial Ca 2+ uptake following a 1 -ARS. We also confirmed the MCU topology at IMM and detailed mPyk2 submitochondrial localization: (i) MCU termini are located at the matrix side as reported (9,11,46), (ii) mPyk2 is predominantly localized in the matrix, and (iii) Phe stimulation induces Pyk2 translocation from the cytosol to matrix. This observation suggests that Pyk2 can interact with MCU from the matrix side and directly phosphorylate the channel on either the N-or C-termini, which are known to be important for channel function (12).…”

Mitochondrial calcium uniporter regulator 1 (MCUR1) regulates the calcium threshold for the mitochondrial permeability transition

“…Stable lines were not clonal, as attempts to isolate individual clones led to loss of cell adherence and failure to expand. For the first hypothesis, we expressed human MCU, the pore-forming subunit of the mitochondrial Ca 2+ uniporter that mediates the mitochondrial Ca 2+ -selective current (20)(21)(22)(23). For the second, we expressed human PPIF, because of the known MPT regulators, this homolog diverged most from its Drosophila counterpart.…”

Itraconazole suppresses the growth of glioblastoma through induction of autophagy

“…37 In contrast, both GAPDH (a cytosolic protein) and MT-CO1 (mitochondrially encoded cytochrome c oxidase I; a mitochondrial membrane protein) were rarely detected in the isolated plasma membrane, confirming the purity of the isolated plasma membrane. 38,39 Treatment with itraconazole resulted in a marked reduction of plasma membrane cholesterol, compared with the DMSO-treated control group (Fig. 7B).…”