title: T lymphocyte activation signals.
abstract: Activation of T lymphocytes results in immediate biochemical changes including increases in intracellular calcium levels, activation of protein kinase C (PKC) and changes in tyrosine phosphorylation. In T cells recent studies have indicated that activation of the guanine nucleotide-binding proteins p21ras is mediated by PKC, which suggests that the p21ras proteins may regulate intracellular signalling events downstream of PKC. The p21ras proteins can be activated in T cells by signals generated by triggering of the T cell antigen receptor (TCR), the CD2 antigen and the interleukin 2 receptor. Experiments using a PKC pseudosubstrate inhibitor indicate that PKC does not mediate TCR-induced activation of p21ras. These results imply that an alternative signal transduction pathway not involving PKC can regulate the activity of p21ras proteins in T cells.
authors.affiliation: Lymphocyte Activation Laboratory, Imperial Cancer Research Fund, London, UK.
authors.forename: D A
authors.initials: DA
authors.lastname: Cantrell
authors.forename: J D
authors.initials: JD
authors.lastname: Graves
authors.forename: M
authors.initials: M
authors.lastname: Izquierdo
authors.forename: S
authors.initials: S
authors.lastname: Lucas
authors.forename: J
authors.initials: J
authors.lastname: Downward
mesh_terms: D006801:Humans; D008213:Lymphocyte Activation / Q000502:physiology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000378:metabolism / Q000502:physiology*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D011948:Receptors, Antigen, T-Cell; D011493:Protein Kinase C; D010738:Type C Phospholipases