Oligomerization of sarcoplasmic reticulum Ca2+-ATPase from rabbit skeletal muscle.
Although the primary structure and catalytic cycle of the sarcoplasmic reticulum Ca2+-ATPase has been revealed, it is not well understood whether functional Ca2+ pump proteins exist in a monomeric or an oligomeric state in native skeletal muscle membranes. Here, we show that the Ca2+-ATPase tends to form high molecular weight complexes, estimated to be dimers and tetramers using immunoblotting of two-dimensionally separated microsomal membranes following crosslinking. This agrees with both electron microscopical and biochemical findings which demonstrate that Ca2+-ATPase clusters are the predominant molecular species in native membranes and that oligomerization may play a role in cooperative kinetics and enzyme stabilization.
Department of Pharmacology, University College Dublin, Belfield, Ireland.
P B
PB
Maguire
K
K
Ohlendieck
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000737:chemistry*; D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D046911:Macromolecular Substances; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000201:enzymology*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013388:Succinimides
D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D013388:Succinimides; C035759:3,3'-dithiobis(sulfosuccinimidyl propionate); D000252:Calcium-Transporting ATPases; C011240:dithiobis(succinimidylpropionate)