Identification of pro-interleukin 16 as a novel target of MAP kinases in activated T lymphocytes.
T lymphocyte activation is controlled by a coordinated web of tyrosine and serine kinases. There is a large body of information about tyrosine kinase substrates in T cells but analysis of serine kinase substrates has been more difficult. Recently we described an antiserum that recognizes serine-phosphorylated peptides corresponding to the substrate sequences for AGC serine kinases. This antiserum, termed PAP-1 (phospho antibody for proteomics-1), has proven useful for probing the serine phosphoproteome of antigen receptor-activated T lymphocytes. The present study shows that PAP-1 can also be used to explore serine kinases activated by cytokines and chemokines in T cells. Using PAP-1, together with proteomic analysis, the precursor form of the cytokine IL-16 (ProIL-16) was shown to be phosphorylated on Ser144 in antigen receptor-, SDF1alpha- and IL-2-activated T cells. Genetic and pharmacological-inhibitor experiments showed that the phosphorylation of ProIL-16 is dependent on activation of the kinases Erk1/2. IL-16 is secreted by mitogen-activated T cells, and the biochemical link between ProIL-16 and Erk1/2, revealed by studies with PAP-1, prompted analysis of the role of MAP kinases in this response. We show that TCR-mediated secretion of IL-16 is dependent on MAP kinases. The present study thus reveals how phosphoproteomic analysis opens previously unrecognized avenues for research, and yields novel insights about targets for MAP kinases in T lymphocytes.
Laurence
Arian
A
Lymphocyte Activation Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London, GB.
Astoul
Emmanuelle
E
Hanrahan
Sarah
S
Totty
Nick
N
Cantrell
Doreen
D
D015153:Blotting, Western; D002847:Chromatography, Agarose; D002867:Chromones / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D019410:Interleukin-16 / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000276:immunology; D020928:Mitogen-Activated Protein Kinases / Q000276:immunology / Q000378:metabolism*; D009025:Morpholines / Q000494:pharmacology; D009930:Organic Chemicals / Q000494:pharmacology; D000073718:Pancreatitis-Associated Proteins; D010766:Phosphorylation; D011233:Precipitin Tests; D011498:Protein Precursors / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013601:T-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism
D002867:Chromones; D004791:Enzyme Inhibitors; D019410:Interleukin-16; D009025:Morpholines; D009930:Organic Chemicals; C466090:PD 98058; D000073718:Pancreatitis-Associated Proteins; D011498:Protein Precursors; C000612141:REG3A protein, human; C105950:interleukin 16 precursor; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D012694:Serine; D020928:Mitogen-Activated Protein Kinases