Analysis of T cell signaling by class I MHC molecules: the cytoplasmic domain is not required for signal transduction.
The structural requirements for signal transduction by class I major histocompatibility complex (MHC) molecules were examined. Native or mutant HLA-A2 or HLA-B27 constructs lacking most of their cytoplasmic domains were co-transfected with pSV2neo into Jurkat cells. Transfection of either native or mutant constructs resulted in a comparable expression of the gene products. Stimulation of transfectants expressing either native or truncated A2 or B27 molecules with specific mAb evoked an increase in [Ca2+]i upon crosslinking. Moreover, crosslinking native or truncated A2 or B27 induced IL-2 production upon co-stimulation with phorbol myristate acetate. These results confirm that crosslinking class I MHC molecules transduces an activation signal to human T cells. Effective signaling was observed when all but four of the intracytoplasmic residues were deleted, indicating that signal transduction does not require this portion of the molecule.
Harold C. Simmons Arthritis Research Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235.
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H
Gur
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el-Zaatari
T D
TD
Geppert
M C
MC
Wacholtz
J D
JD
Taurog
P E
PE
Lipsky
D000818:Animals; D002118:Calcium / Q000032:analysis; D003593:Cytoplasm / Q000502:physiology; D015789:HLA-A2 Antigen / Q000235:genetics / Q000502:physiology*; D015796:HLA-B27 Antigen / Q000235:genetics / Q000502:physiology*; D007376:Interleukin-2 / Q000096:biosynthesis; D051379:Mice; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D015789:HLA-A2 Antigen; D015796:HLA-B27 Antigen; D007376:Interleukin-2; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium