Cluster formation by protein kinase Ctheta during murine T cell activation: effect of age.
Protein kinase Ctheta; (PKCtheta;) is thought to play an important role in T cell activation, in that exposure of cloned T cells to antigen-presenting cells bearing agonist peptides, but not antagonist peptides, leads to clustering of PKCtheta; molecules in the section of the T cell plasma membrane that is in contact with the APCs. To see whether aging affects this PKCtheta; clustering reaction in mouse T lymphocytes, we used immunofluorescence staining and confocal microscopy to observe the localization of PKCtheta; in CD4 and CD8 T lymphocytes activated by coincubation with anti-CD3 hybridoma cells. Aging led to a twofold decline in the proportion of both CD4 and CD8 T cells in which PKCtheta; underwent cluster formation. This decrease with age was not due to differences in the number of cell conjugates formed, nor to kinetic differences of PKCtheta; clustering, nor to the accumulation of memory T cells in old mice. There were no effects of aging on the levels or kinase activity of PKCtheta; in murine T cells. Our data suggest alterations in the upstream signals that regulate PKCtheta; translocation.
Yang
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Department of Pathology, University of Michigan, Ann Arbor, Michigan, 48109-0940, USA.
Miller
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RA
D000375:Aging / Q000276:immunology*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000201:enzymology* / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000201:enzymology* / Q000276:immunology; D004789:Enzyme Activation; D006825:Hybridomas; D007527:Isoenzymes / Q000096:biosynthesis / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011493:Protein Kinase C / Q000096:biosynthesis / Q000378:metabolism*; D000074121:Protein Kinase C-theta; D051381:Rats; D013154:Spleen / Q000276:immunology
D007527:Isoenzymes; C489593:Prkcq protein, mouse; C489591:Prkcq protein, rat; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta