The putative role of phospholamban in the regulation of the heart muscle.
We describe the 50fold purification of phospholamban, the production of antibodies against it and preliminary experiments of reconstitution of purified phospholamban into vesicles of skeletal sarcoplasmic reticulum (SR). Purified phospholamban migrates in a modified Laemmli SDS polyacrylamide gel electrophoresis (PAGE) system with a relative molecular mass (Mr) of 22 kD and 6 kD. The higher Mr form is detectable by immunoreaction on Western blots only in heart SR preparations, whereas the low Mr form is also present in sarcolemmal preparations. No immunoreactivity was found in SR of skeletal muscle. Reconstituted skeletal SR vesicles were not influenced by phospholamban in respect to their Ca++-ATPase activity and calcium accumulation rate, but the obtained data suggest that phospholamban alters the calcium storage capacity of SR.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000276:immunology / Q000302:isolation & purification / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D008970:Molecular Weight; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D010766:Phosphorylation; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013552:Swine; D000099211:Phospholamban
D002118:Calcium; D002135:Calcium-Binding Proteins; D000252:Calcium-Transporting ATPases; D000099211:Phospholamban