T cell receptor delta diversity 1 (TRDD1)

D region of the variable domain of T cell receptor (TR) delta chain that engages in the antigen recognition (PubMed:24600447). Gamma-delta TRs recognize a variety of self and foreign non-peptide antigens frequently expressed at the boundaries between the host and external environment, including endogenous lipids introduced by MH-like protein CD1D and phosphoantigens introduced by butyrophilin-like molecule BTN3A1.

Binding of gamma-delta TR complex to antigen activates phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) in the CD3 chains by the LCK and FYN kinases, permitting the recruitment, phosphorylation, and activation of ZAP70 that facilitates phosphorylation of the scaffolding proteins LCP2 and LAT. This lead to the formation of a supramolecular signalosome that recruits the phospholipase PLCG1, leading to calcium mobilization and ERK activation, ultimately leading to T cell growth and differentiation into effector cells (PubMed:25674089).