1.A.62.1.4
TRICB1 and TRICB2 of 313 aas and 295 aas, respectively. Yang et al. 2016 presented the structures of TRIC-B1 and TRIC-B2 channels from Caenorhabditis elegans in complex with endogenous phosphatidylinositol-4,5-biphosphate (PtdIns(4,5)P2, also known as PIP2) lipid molecules. The TRIC-B1/B2 proteins and PIP2 assemble into a symmetrical homotrimeric complex. Each monomer contains an hourglass-shaped hydrophilic por within a seven-transmembrane-helix domain. Structural and functional analyses revealed the central role of PIP2 in stabilizing the cytoplasmic gate of the ion permeation pathway and showed a marked Ca²⁺-induced conformational change in a cytoplasmic loop above the gate. A mechanistic model was proposed to account for the complex gating mechanism of TRIC channels (Yang et al. 2016).