tailieunhanh - Báo cáo khoa học: Mitochondrial affinity for ADP is twofold lower in creatine kinase knock-out muscles Possible role in rescuing cellular energy homeostasis

Adaptations of the kinetic properties of mitochondria in striated muscle lacking cytosolic (M) and⁄or mitochondrial (Mi) creatine kinase (CK) iso-forms in comparison to wild-type (WT) were investigated in vitro. Intact mitochondria were isolated from heart and gastrocnemius muscle of WT and single- and double CK-knock-out mice strains (cytosolic (M-CK –⁄ – ), mitochondrial (Mi-CK –⁄ – ) and double knock-out (MiM-CK –⁄ – ), respect-ively). | iFEBS Journal Mitochondrial affinity for ADP is twofold lower in creatine kinase knock-out muscles Possible role in rescuing cellular energy homeostasis Frank ter Veld1 Jeroen A. L. Jeneson2 3 and Klaas Nicolay3 1 Department of Experimentalln Vivo NMR Image Sciences Institute University MedicalCenter Utrecht the Netherlands 2 Department of Physiology Schoolof Veterinary Medicine Utrecht University the Netherlands 3 BiomedicalNMR Department of BiomedicalEngineering Eindhoven University of Technology the Netherlands Keywords heart metabolic control mitochondrial respiration skeletal muscle transgenic mice Correspondence F. ter Veld Laboratory for Biophysics and CellBiology Department of EpithelialCell Physiology Max Planck Institute of Molecular Physiology Otto-Hahn-Strasse 11 D-44227 Dortmund Germany Fax 49 231133 2299 Tel 49 231133 2226 E-mail Received 30 July 2004 revised 8 December 2004 accepted 14 December 2004 doi Adaptations of the kinetic properties of mitochondria in striated muscle lacking cytosolic M and or mitochondrial Mi creatine kinase CK isoforms in comparison to wild-type WT were investigated in vitro. Intact mitochondria were isolated from heart and gastrocnemius muscle of WT and single- and double CK-knock-out mice strains cytosolic M-CK mitochondrial Mi-CK and double knock-out MiM-CK7 . respectively . Maximal ADP-stimulated oxygen consumption flux State3 Vmax nmol O2-mg mitochondrial protein-1-min-1 and ADP affinity K50ADP pM were determined by respirometry. State 3 Vmax and K50ADP of M-CK- -and MiM-CK- - gastrocnemius mitochondria were twofold higher than those of WT but were unchanged for Mi-CK- -. For mutant cardiac mitochondria only the K50ADP of mitochondria isolated from the MiM-CK- -phenotype was different . twofold higher than that of WT. The implications of these adaptations for striated muscle function were explored by constructing force-flow relations of skeletal .