The interactions between mitochondria and sarcoplasmic reticulum and the proteome characterization of mitochondrion-associated membrane from rabbit skeletal muscle

To obtain a comprehensive understanding of proteins involved in mitochondrion-sarcoplasmic reticulum (SR) linking, a catalog of proteins from mitochondrion-associated membrane (MAM) of New Zealand white rabbit skeletal muscle were analyzed by an optimized shotgun proteomic method. The membrane fractions were prepared by differential centrifugation and separated by 1D electrophoresis followed by a highly reproducible, automated LC-MS/MS on the hybrid linear ion trap (LTQ)-Orbitrap mass spectrometer. By integrating as low as 1% false discovery rate as one of the features for quality control method, 459 proteins were identified from both of the two independent MAM preparations. Protein pI value, molecular weight range, and transmembrane region were calculated using bioinformatics softwares. One hundred one proteins were recognized as membrane proteins. This protein database suggested that the MAM preparations composed of proteins from mitochondrion, SR, and transverse-tubule. This result indicated mitochondria physically linked with SR in rabbit skeletal muscle, voltage-dependent anion channel 1 (VDAC1), VDAC2, and VDAC3 might participate in formation of the tethers between SR and mitochondria.