Structural highlights
Function
[SCMC1_HUMAN] Calcium-dependent mitochondrial solute carrier. Mitochondrial solute carriers shuttle metabolites, nucleotides, and cofactors through the mitochondrial inner membrane. May act as a ATP-Mg/Pi exchanger that mediates the transport of Mg-ATP in exchange for phosphate, catalyzing the net uptake or efflux of adenine nucleotides into or from the mitochondria.[1]
Publication Abstract from PubMed
The mitochondrial carriers play essential roles in energy metabolism. The short Ca(2+)-binding mitochondrial carrier (SCaMC) transports ATP-Mg in exchange for Pi and is important for activities that depend on adenine nucleotides. SCaMC adopts, in addition to the transmembrane domain (TMD) that transports solutes, an extramembrane N-terminal domain (NTD) that regulates solute transport in a Ca(2+)-dependent manner. Crystal structure of the Ca(2+)-bound NTD reveals a compact architecture in which the functional EF hands are sequestered by an endogenous helical segment. Nuclear magnetic resonance (NMR) relaxation rates indicated that removal of Ca(2+) from NTD results in a major conformational switch from the rigid and compact Ca(2+)-bound state to the dynamic and loose apo state. Finally, we showed using surface plasmon resonance and NMR titration experiments that free apo NTDs could specifically interact with liposome-incorporated TMD, but that Ca(2+) binding drastically weakened the interaction. Our results together provide a molecular explanation for Ca(2+)-dependent ATP-Mg flux in mitochondria.
A Self-Sequestered Calmodulin-like Ca(2+) Sensor of Mitochondrial SCaMC Carrier and Its Implication to Ca(2+)-Dependent ATP-Mg/Pi Transport.,Yang Q, Bruschweiler S, Chou JJ Structure. 2014 Feb 4;22(2):209-17. doi: 10.1016/j.str.2013.10.018. Epub 2013 Dec, 12. PMID:24332718[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Fiermonte G, De Leonardis F, Todisco S, Palmieri L, Lasorsa FM, Palmieri F. Identification of the mitochondrial ATP-Mg/Pi transporter. Bacterial expression, reconstitution, functional characterization, and tissue distribution. J Biol Chem. 2004 Jul 16;279(29):30722-30. Epub 2004 Apr 29. PMID:15123600 doi:http://dx.doi.org/10.1074/jbc.M400445200
- ↑ Yang Q, Bruschweiler S, Chou JJ. A Self-Sequestered Calmodulin-like Ca(2+) Sensor of Mitochondrial SCaMC Carrier and Its Implication to Ca(2+)-Dependent ATP-Mg/Pi Transport. Structure. 2014 Feb 4;22(2):209-17. doi: 10.1016/j.str.2013.10.018. Epub 2013 Dec, 12. PMID:24332718 doi:http://dx.doi.org/10.1016/j.str.2013.10.018
