title: Subcellular localization and translocation of protein kinase C isoforms zeta and epsilon in human peripheral blood lymphocytes.
abstract: The calcium-independent members of the protein kinase C (PKC) family may play a significant role in T cell function. We have characterized the subcellular localization and redistribution of calcium-independent kinase C activity and of two specific members of this family (zeta and epsilon) in response to activation of human peripheral blood lymphocytes with phorbol myristate acetate (PMA) or through the TCR-CD3 complex. Both PMA and OKT3, an antibody against the TCR-associated CD3 complex, induce an increase in membrane and cytoskeletal activity with a concomitant decrease in cytosolic activity. By Western blot analysis, PKC epsilon is present in resting cytosol and membrane fractions, and is detected in the membrane following activation with PMA and in both the membrane and cytoskeleton following OKT3 activation. By contrast, PKC zeta is progressively lost from the cytoskeleton following activation with anti-CD3. Immunocytochemistry reveals distinct redistribution patterns for these enzymes in response to activation through anti-CD3 and by PMA. These findings demonstrate that signaling through the CD3 complex induces significant changes in calcium-independent PKC activity and in the intracellular distribution of specific isoenzymes, and support a role for specific functions for individual isoenzymes in T cell activation. Lastly, changes in the cytoskeletal distribution of these isoenzymes suggest a potential role in the modulation of cell structure in response to activation.
authors.affiliation: Department of Clinical Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St James's Hospital, Ireland.
authors.forename: C
authors.initials: C
authors.lastname: Keenan
authors.forename: Y
authors.initials: Y
authors.lastname: Volkov
authors.forename: D
authors.initials: D
authors.lastname: Kelleher
authors.forename: A
authors.initials: A
authors.lastname: Long
mesh_terms: D001693:Biological Transport, Active; D017252:CD3 Complex / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000097:blood*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000502:physiology; D008214:Lymphocytes / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology; D011493:Protein Kinase C / Q000097:blood*; D051744:Protein Kinase C-epsilon; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000099221:Protein Kinase C zeta
chemical_list: D017252:CD3 Complex; D007527:Isoenzymes; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; D011948:Receptors, Antigen, T-Cell; D013755:Tetradecanoylphorbol Acetate; D000099221:Protein Kinase C zeta; C497255:PRKCE protein, human