Changes in the mitochondrial proteome from mouse hearts deficient in creatine kinase

Creatine kinase (CK) is an abundant enzyme, important for maintenance of hi gh-energy phosphate homeostasis in many tissues including heart. Double-kno ckout CK (DbKO-CK) mice missing both the muscle (MM) and sarcomeric mitocho ndrial (ScMit) isoforms of CK have recently been studied. Despite a large c hange in skeletal muscle function in DbKO-CK mice, there is little function al change in the heart. To investigate whether there are specific changes i n cardiac mitochondrial proteins associated with the loss of MM- and ScMit- CK isoforms, we have used difference gel electrophoresis (DIGE) to compare mitochondrial proteins from wild-type and DbKO-CK mice. Mass spectrometry f ingerprinting was used to identify 40 spots as known mitochondrial proteins . We have discovered that the loss of MM- and ScMit-CK isoforms did not cau se large scale changes in heart mitochondrial proteins. The loss of ScMit-C K was readily detected in the DbKO-CK samples. We have also detected a larg e decrease in the precursor form of aconitase. Furthermore, two mitochondri al protein differences have been found in the parent mouse strains of the D bKO-CK mice.