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Publication Abstract from PubMed

Cholesterol molecules specifically bind to the resting alphabetaTCR to inhibit cytoplasmic CD3zeta ITAM phosphorylation through sequestering the TCR-CD3 complex in an inactive conformation. The mechanisms of cholesterol-mediated inhibition of TCR-CD3 and its activation remain unclear. Here, we present cryoelectron microscopy structures of cholesterol- and cholesterol sulfate (CS)-inhibited TCR-CD3 complexes and an auto-active TCR-CD3 variant. The structures reveal that cholesterol molecules act like a latch to lock CD3zeta into an inactive conformation in the membrane. Mutations impairing binding of cholesterol molecules to the tunnel result in the movement of the proximal C terminus of the CD3zeta transmembrane helix, thereby activating the TCR-CD3 complex in human cells. Together, our data reveal the structural basis of TCR inhibition by cholesterol, illustrate how the cholesterol-binding tunnel is allosterically coupled to TCR triggering, and lay a foundation for the development of immunotherapies through directly targeting the TCR-CD3 complex.

Cholesterol inhibits TCR signaling by directly restricting TCR-CD3 core tunnel motility.,Chen Y, Zhu Y, Li X, Gao W, Zhen Z, Dong D, Huang B, Ma Z, Zhang A, Song X, Ma Y, Guo C, Zhang F, Huang Z Mol Cell. 2022 Apr 7;82(7):1278-1287.e5. doi: 10.1016/j.molcel.2022.02.017. Epub , 2022 Mar 9. PMID:35271814^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.