4ono
From Proteopedia
CD1c in complex with PM (phosphomycoketide)
Structural highlights
DiseaseB2MG_HUMAN Defects in B2M are the cause of hypercatabolic hypoproteinemia (HYCATHYP) [MIM:241600. Affected individuals show marked reduction in serum concentrations of immunoglobulin and albumin, probably due to rapid degradation.[1] Note=Beta-2-microglobulin may adopt the fibrillar configuration of amyloid in certain pathologic states. The capacity to assemble into amyloid fibrils is concentration dependent. Persistently high beta(2)-microglobulin serum levels lead to amyloidosis in patients on long-term hemodialysis.[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] FunctionCD1C_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.[15] [16] [17] [18] CD1B_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.[19] [20] B2MG_HUMAN Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. Publication Abstract from PubMedCD1c is a member of the group 1 CD1 family of proteins that are specialized for lipid antigen presentation. Despite high cell surface expression of CD1c on key antigen-presenting cells and the discovery of its mycobacterial lipid antigen presentation capability, the molecular basis of CD1c recognition by T cells is unknown. Here we present a comprehensive functional and molecular analysis of alphabeta T-cell receptor (TCR) recognition of CD1c presenting mycobacterial phosphomycoketide antigens. Our structure of CD1c with the mycobacterial phosphomycoketide (PM) shows similarities to that of CD1c-mannosyl-beta1-phosphomycoketide in that the A' pocket accommodates the mycoketide alkyl chain; however, the phosphate head-group of PM is shifted approximately 6 A in relation to that of mannosyl-beta1-PM. We also demonstrate a bona fide interaction between six human TCRs and CD1c-mycoketide complexes, measuring high to moderate affinities. The crystal structure of the DN6 TCR and mutagenic studies reveal a requirement of five complementarity determining region (CDR) loops for CD1c recognition. Furthermore, mutagenesis of CD1c reveals residues in both the alpha1 and alpha2 helices involved in TCR recognition, yet not entirely overlapping among the examined TCRs. Unlike patterns for MHC I, no archetypical binding footprint is predicted to be shared by CD1c-reactive TCRs, even when recognizing the same or similar antigens. Molecular basis of mycobacterial lipid antigen presentation by CD1c and its recognition by alphabeta T cells.,Roy S, Ly D, Li NS, Altman JD, Piccirilli JA, Moody DB, Adams EJ Proc Natl Acad Sci U S A. 2014 Oct 28;111(43):E4648-57. doi:, 10.1073/pnas.1408549111. Epub 2014 Oct 8. PMID:25298532[21] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations 24 reviews cite this structure No citations found See AlsoReferences
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