Abstract
EVERY cell contains many families of protein kinases, and may express several structurally related yet genetically distinct kinases of each family. The activity of the serine/threonine protein kinase C (PKC) enzymes has long been implicated in T-cell activation, but it is not known which members of the PKC family regulate the T-cell response to foreign antigens. The activation of T cells by antigen-presenting cells (APCs) is spatially restricted to their site of contact, where receptors on the T cells engage their counter-receptors on the APCs. We used this localized engagement to identify, at the single-cell level, intracellular proteins involved in the activation process. By digital immunofluorescence microscopy, we localized six isoforms of PKC in antigen-specific T-cell clones activated by APCs. Surprisingly, only PKC-θ translocated to the site of cell contact. Accordingly, in vitro kinase activity assays of PKC immunoprecipitates from the conjugates of T cells and APCs showed a selective increase in the activity of PKC-θ, indicating that the translocated enzyme is active. Several modes of partial T-cell activation that failed to cause PKC-θ translocation also failed to cause T-cell proliferation, further suggesting the involvement of PKC-θ in T-cell activation.
Original language | English (US) |
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Pages (from-to) | 83-86 |
Number of pages | 4 |
Journal | Nature |
Volume | 385 |
Issue number | 6611 |
DOIs | |
State | Published - Jan 2 1997 |
Externally published | Yes |
ASJC Scopus subject areas
- General