5. Partially folded HLA-B27 molecules, linked by the relatively unique cysteine 67 residue in the peptide-binding groove have been detected both in vitro and in vivo,8,9,33,34 and may be a contributory factor to the development of the arthritic condition ankylosing spondylitis, either by altered NK receptor recognition at the cell surface,35 or by induction of
intracellular unfolded protein cellular stress responses.36 HLA-G molecules form unique dimers by disulphide linkage at position 42 on PF-02341066 clinical trial an external loop of the peptide-binding groove.12 These dimers may be relevant in tolerizing signals in pregnancy and in regulatory T-cell subsets.11,37 Lastly, a population of folded MHC class I dimers can exist on exosomes and redox-altered normal cells, and apoptotic cells, induced by disulphide linkages between cysteines in the cytoplasmic tails.15 The work in this study was funded in part by the Chief Scientist’s Office (CSO) of Napabucasin the Scottish Government. No competing financial interests exist. “
“Signals from the T-cell recognition
of antigen program effector functions are necessary to clear infections and tumors. The JNK pathway is critically important in regulating this process. In T lymphocytes, JNK1 and JNK2 have distinct functions depending on their maturation state and cell-type. However, the mechanisms that regulate their isoform-specific activity and function are still unclear. Here, we identify plenty of SH3 (POSH) and JNK-interacting protein 1 (JIP-1) as a multiprotein scaffold network for TCR-mediated JNK1 activation in CD8+ T cells. Disruption of the POSH/JIP-1 complex led to profound defects in the activation of JNK1, as well as deficient activation or induction of the transcription factors c-Jun, T-bet, and Eomesodermin. Furthermore, disruption of the POSH/JIP complex in CD8+ T cells resulted in impaired proliferation, decreased cytokine expression, and the inability to control tumors. Collectively,
these data identify a mechanism for the specific regulation of TCR-dependent JNK1 activation and function that is key for CD8+ T-cell responses. Upon infection, T-cell activation and differentiation are initiated through TCR engagement of peptide-MHC molecules on the surface of Endonuclease APCs in the context of co-stimulation and inflammatory cytokines. These cues trigger numerous signal transduction cascades, whose integration is “translated” into changes in gene transcription, protein activity, and expression. This ultimately leads to the development of effector function and T-cell-mediated immunity [1]. The MAPK SAPK/JNK cascade plays a major role in regulating a variety of fate decisions including activation, proliferation, differentiation, and death [2, 3]. Three genes encode the JNK family members. JNK1 and JNK2 are ubiquitously expressed, whereas the expression of JNK3 is restricted to the brain, heart, and testis [2].