Immunolocalization of meta-vinculin in human smooth and cardiac muscles.
Meta-vinculin, a vinculin-related protein, has been isolated from human uterus smooth muscle. Specific antibodies to meta-vinculin, which distinguish between meta-vinculin and vinculin, were prepared by absorption of anti-meta-vinculin serum on vinculin coupled to nitrocellulose. Meta-vinculin specific antibody demonstrates only smooth and cardiac muscle specificity and is able to cross-react with a small 21-kD fragment of the meta-vinculin polypeptide chain. This antibody does not interact with protease resistant 95-kD core shared by vinculin and meta-vinculin. Meta-vinculin specific antibody was used for the localization of meta-vinculin in smooth and cardiac muscles by the indirect immunofluorescence method. At the light microscopy resolution level it was found that meta-vinculin and vinculin are localized in the same cellular adhesive structures. Meta-vinculin is present in membrane-associated microfilament-bound plaques of smooth muscle, in intercalated discs and costameres of cardiac muscle. In primary culture of smooth muscle cells from human aorta, meta-vinculin and vinculin were found to be present in focal contacts of the cells. During the cultivation of smooth muscle cells, the quantity of meta-vinculin decreased progressively and finally meta-vinculin completely disappeared from the focal contacts. The data show that in smooth and cardiac muscles meta-vinculin could be a structural component of microfilament-membrane attachment sites, defined earlier by the localization of vinculin.
D000918:Antibody Specificity; D001011:Aorta; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007118:Immunoassay; D007150:Immunohistochemistry; D007525:Isoelectric Focusing; D008565:Membrane Proteins / Q000032:analysis*; D009124:Muscle Proteins / Q000032:analysis* / Q000276:immunology; D009130:Muscle, Smooth / Q000032:analysis*; D009131:Muscle, Smooth, Vascular / Q000032:analysis; D009132:Muscles / Q000032:analysis; D009206:Myocardium / Q000032:analysis*; D014599:Uterus; D016596:Vinculin
D008565:Membrane Proteins; D009124:Muscle Proteins; C488955:VCL protein, human; D016596:Vinculin