The Cish SH2 domain is essential for PLC-gamma 1 regulation in TCR stimulated CD8(+) T cells

Geoffrey Guittard (1, 2) , Ana Dios-Esponera (2) , Douglas C. Palmer (2) , Itoro Akpan (2) , Valarie A. Barr (2) , Asit Manna (2) , Nicholas P. Restifo (2) , Lawrence E. Samelson (2)

1 CRCM - Centre de Recherche en Cancérologie de Marseille
2 NIH - National Institutes of Health [Bethesda, MD, USA]

Cish, participates within a multi-molecular E3 ubiquitin ligase complex, which ubiquitinates target proteins. It has an inhibitory effect on T cell activation mediated by PLC-gamma 1 regulation, and it functions as a potent checkpoint in CD8(+) T cell tumor immunotherapy. To study the structural and functional relationships between Cish and PLC-gamma 1 during CD8(+) T cell activation, we tested mutants of the Cish-SH2 (R107K) and D/BC (L222Q, C226Q) domains. We confirmed that Cish-SH2-specific binding was essential for PLC-gamma 1 ubiquitination and degradation. This domain was essential for the Cish-mediated inhibition of Ca2+ release upon TCR stimulation. No effect on inhibition of cytokine release was observed with SH2 or D/BC mutants, although the absence of Cish led to an increased release of IFN-gamma and TNF-alpha. Using imaging we showed that Cish was expressed mostly in the cytoplasm and we did not see any Cish clustering at the plasma membrane upon stimulation. We conclude that the Cish-SH2 domain is essential for PLC-gamma 1 regulation in TCR-stimulated CD8(+) T cells.

Mots clés: Cytotoxic T cells; Signal transduction

Domaines: Sciences du Vivant [q-bio]

Geoffrey Guittard, Ana Dios-Esponera, Douglas C. Palmer, Itoro Akpan, Valarie A. Barr, et al.. The Cish SH2 domain is essential for PLC-gamma 1 regulation in TCR stimulated CD8(+) T cells. Scientific Reports, 2018, 8 (5336), ⟨10.1038/s41598-018-23549-2⟩. ⟨hal-02143617⟩