Octameric mitochondrial creatine kinase induces and stabilizes contact sites between the inner and outer membrane.
We have investigated the role of the protein ubiquitous mitochondrial creatine kinase (uMtCK) in the formation and stabilization of inner and outer membrane contact sites. Using liver mitochondria isolated from transgenic mice, which, unlike control animals, express uMtCK in the liver, we found that the enzyme was associated with the mitochondrial membranes and, in addition, was located in membrane-coated matrix inclusions. In mitochondria isolated from uMtCK transgenic mice, the number of contact sites increased 3-fold compared with that observed in control mitochondria. Furthermore, uMtCK-containing mitochondria were more resistant to detergent-induced lysis than wild-type mitochondria. We conclude that octameric uMtCK induces the formation of mitochondrial contact sites, leading to membrane cross-linking and to an increased stability of the mitochondrial membrane architecture.
Swiss Federal Institute of Technology, ETH-Zürich, Institute of Cell Biology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland. Oliver.Speer@molbio.unizh.ch
Oliver
O
Speer
Nils
N
Bäck
Tanja
T
Buerklen
Dieter
D
Brdiczka
Alan
A
Koretsky
Theo
T
Wallimann
Ove
O
Eriksson
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology; D003402:Creatine Kinase / Q000502:physiology*; D007425:Intracellular Membranes / Q000201:enzymology* / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008854:Microscopy, Electron / Q000379:methods; D008928:Mitochondria / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D008929:Mitochondria, Heart / Q000201:enzymology / Q000648:ultrastructure; D008930:Mitochondria, Liver / Q000201:enzymology / Q000648:ultrastructure; D024101:Mitochondrial Proteins / Q000502:physiology
D024101:Mitochondrial Proteins; D003402:Creatine Kinase