Elsevier

Experimental Cell Research

Volume 210, Issue 2, February 1994, Pages 287-297
Experimental Cell Research

Regular Article
Localization of Protein Kinase C Isozymes in Cardiac Myocytes

https://doi.org/10.1006/excr.1994.1041Get rights and content
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Abstract

Activation of protein kinase C (PKC) isozymes is associated with their translocation from the cell-soluble fraction to the cell-particulate fraction, presumably near their protein substrates. Therefore, identifying the subcellular localization of each activated PKC isozyme may help to elucidate its role in cardiac functions. In the present work, we have determined the subcellular localization of six PKC isozymes (α, βI, βII, δ, ϵ, and ζ) in nonstimulated cardiac myocytes and in myocytes stimulated by norepinephrine (2 μM) or phorbol 12-myristate 13-acetate (100 nM). Activated PKC isozymes were localized in various subcellular compartments such as inside the nucleus and on myofibrils. The presence of serum in the growth medium also caused a redistribution of PKC isozymes in the cells distinct from that obtained with cells cultured in defined medium. We suggest that isozyme-specific localization may determine phosphorylation of different protein substrates present at these respective translocation sites and the resulting PKC-mediated cellular responses.

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