CD28 plays a critical role in the segregation of PKC theta within the immunologic synapse.
The signaling pathways that lead to the localization of cellular protein to the area of interaction between T cell and antigen-presenting cell and the mechanism by which these molecules are further sorted to the peripheral supramolecular activation cluster or central supramolecular activation cluster regions of the immunologic synapse are poorly understood. In this study, we investigated the functional involvement of CD28 costimulation in the T cell receptor (TCR)-mediated immunologic synapse formation with respect to protein kinase C (PKC)theta; localization. We showed that CD3 crosslinking alone was sufficient to induce PKC theta; capping in naive CD4(+) T cells. Studies with pharmacologic inhibitors and knockout mice showed that the TCR-derived signaling that drives PKC theta; membrane translocation requires the Src family kinase, Lck, but not Fyn. In addition, a time course study of the persistence of T cell molecules to the immunologic synapse indicated that PKC theta;, unlike TCR, persisted in the synapse for at least 4 h, a time that is sufficient for commitment of a T cell to cell division. Finally, by using TCR-transgenic T cells from either wild-type or CD28-deficient mice, we showed that CD28 expression was required for the formation of the mature immunologic synapse, because antigen stimulation of CD28(-) T cells led to a diffuse pattern of localization of PKC theta; and lymphocyte function-associated antigen-1 in the immunologic synapse, in contrast to the central supramolecular activation cluster localization of PKC theta; in CD28(+) T cells.
Huang
Jianyong
J
Division of Immunochemistry, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, CA 92121, USA.
Lo
Pei-Fen
PF
Zal
Tomasz
T
Gascoigne
Nicholas R J
NR
Smith
Brian A
BA
Levin
Steven D
SD
Grey
Howard M
HM
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D018106:CD28 Antigens / Q000235:genetics / Q000378:metabolism*; D017252:CD3 Complex / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000201:enzymology* / Q000276:immunology*; D002462:Cell Membrane / Q000201:enzymology / Q000276:immunology; D007152:Immunologic Capping; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011493:Protein Kinase C / Q000378:metabolism*; D000074121:Protein Kinase C-theta; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
D018106:CD28 Antigens; D017252:CD3 Complex; D007527:Isoenzymes; D016169:Lymphocyte Function-Associated Antigen-1; D011948:Receptors, Antigen, T-Cell; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); C489593:Prkcq protein, mouse; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta