6d64
Crystal Structure of Human CD1b in Complex with POPC
Structural highlights
FunctionCD1B_HUMAN Antigen-presenting protein that binds self and non-self lipid and glycolipid antigens and presents them to T-cell receptors on natural killer T-cells.[1] [2] Publication Abstract from PubMedCD1 proteins are expressed on dendritic cells, where they display lipid antigens to T-cell receptors (TCRs). Here we describe T-cell autoreactivity towards ubiquitous human membrane phospholipids presented by CD1b. These T-cells discriminate between two major types of lipids, sphingolipids and phospholipids, but were broadly cross-reactive towards diverse phospholipids including phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine. The crystal structure of a representative TCR bound to CD1b-phosphatidylcholine provides a molecular mechanism for this promiscuous recognition. We observe a lateral escape channel in the TCR, which shunted phospholipid head groups sideways along the CD1b-TCR interface, without contacting the TCR. Instead the TCR recognition site involved the neck region phosphate that is common to all major self-phospholipids but absent in sphingolipids. Whereas prior studies have focused on foreign lipids or rare self-lipids, we define a new molecular mechanism of promiscuous recognition of common self-phospholipids including those that are known targets in human autoimmune disease. A T-cell receptor escape channel allows broad T-cell response to CD1b and membrane phospholipids.,Shahine A, Reinink P, Reijneveld JF, Gras S, Holzheimer M, Cheng TY, Minnaard AJ, Altman JD, Lenz S, Prandi J, Kubler-Kielb J, Moody DB, Rossjohn J, Van Rhijn I Nat Commun. 2019 Jan 4;10(1):56. doi: 10.1038/s41467-018-07898-0. PMID:30610190[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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