PD-1 inhibits T-cell receptor induced phosphorylation of the ZAP70/CD3zeta signalosome and downstream signaling to PKCtheta
Kelly-Ann Sheppard, Lori J Fitz, Julie M Lee, Christina Benander, Judith A George, Joe Wooters, Yongchang Qiu, Jason M Jussif, Laura L Carter, Clive R Wood, Divya Chaudhary, Kelly-Ann Sheppard, Lori J Fitz, Julie M Lee, Christina Benander, Judith A George, Joe Wooters, Yongchang Qiu, Jason M Jussif, Laura L Carter, Clive R Wood, Divya Chaudhary
Abstract
Engagement of the immunoinhibitory receptor, programmed death-1 (PD-1) attenuates T-cell receptor (TCR)-mediated activation of IL-2 production and T-cell proliferation. Here, we demonstrate that PD-1 modulation of T-cell function involves inhibition of TCR-mediated phosphorylation of ZAP70 and association with CD3zeta. In addition, PD-1 signaling attenuates PKCtheta activation loop phosphorylation in a cognate TCR signal. PKCtheta has been shown to be required for T-cell IL-2 production. A phosphorylated PD-1 peptide, corresponding to the C-terminal immunoreceptor tyrosine-switch motif (ITSM), acts as a docking site in vitro for both SHP-2 and SHP-1, while the phosphorylated peptide containing the N-terminal PD-1 immunoreceptor tyrosine based inhibitory motif (ITIM) associates only with SHP-2.
Source: PubMed