Mg2+ uptake into the mitochondrial matrix occurs via elec-trophoretic uniport, driven by the (inside negative) membrane potential. Intramitochondrial Mg2+ concentrations ([Mg2+]m) are kept close to those in the cytoplasm, and thus far below electrochemical equilibrium. This is indicating that Mg2+ influx into the organelle is tightly controlled. A nuclear gene of the yeast Saccharomyces cerevisiae, named yMRS2, encoded a mitochondrial inner membrane protein mediating Mg2+ influx into this organelle. Activity of this protein is essential for mitochondrial functions, but yeast cells lacking yMrs2 are viable under fermentative growth conditions. The human genome encodes a single expressed homologue (MRS2L) of the yeast protein that has been shown to be an integral protein of the mitochondrial membrane. Low levels of the transcript were detected in various tissues. Expression of the human Mrs2 protein (hMrs2) in yeast mrs2 knockout cells can partially suppress their mitochondrial dysfunction. Accordingly, yMrs2 and hMrs2 appear to be functional homologues. Here you can see a top view of the mitochondrial human Mrs2 channel determined by cryoEM (PDB code: 8IP3)

#molecularart ... #immolecular ... #channel ... #mitochondria ... #magnesium ... #transport ... #cryoem

Structure rendered with @proteinimaging and depicted with @corelphotopaint