Localization of phospholamban in smooth muscle using immunogold electron microscopy.
Phospholamban, the putative regulator of the Ca2+-ATPase in cardiac sarcoplasmic reticulum, was immunolocalized in canine visceral and vascular smooth muscle. Gently disrupted tissues were labeled with an affinity-purified phospholamban polyclonal antibody and indirect immunogold, using preembedding techniques. The sarcoplasmic reticulum of smooth muscle cells was specifically labeled with patches of immunogold distributed in a nonuniform fashion, while the sarcolemma did not appear to contain any phospholamban. The outer nuclear envelopes were also observed to be heavily labeled with the affinity-purified phospholamban polyclonal antibody. These findings suggest that phospholamban may play a role in the regulation of cytoplasmic and intranuclear calcium levels in smooth muscle cells.
Department of Physiology and Biophysics, University of Cincinnati, College of Medicine, Ohio 45267-0576.
D G
DG
Ferguson
E F
EF
Young
L
L
Raeymaekers
E G
EG
Kranias
D000818:Animals; D002135:Calcium-Binding Proteins / Q000032:analysis*; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay; D007082:Ileum; D007118:Immunoassay; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009130:Muscle, Smooth / Q000032:analysis* / Q000648:ultrastructure; D009131:Muscle, Smooth, Vascular / Q000032:analysis* / Q000648:ultrastructure; D013270:Stomach; D013552:Swine; D000099211:Phospholamban
D002135:Calcium-Binding Proteins; D000099211:Phospholamban