8tw4 | pdb_00008tw4
TCR in nanodisc ND-I
Structural highlights
FunctionA0A4D6FVK6_ECOLI TRBR2_HUMAN The beta chain of TRAV38-2DV8*01J31*01C*01/TRBV25-1*01J2S3*01C2*01 alpha-beta T cell receptor (TR) clonotype that displays pan-cancer cell recognition via the invariant MR1 molecule. On CD8-positive T cell clone MC.7.G5, likely recognizes tumor-specific or -associated metabolite(s) essential for cancer cell survival, triggering killing of many cancer cell types including lung, melanoma, leukemia, colon, breast, prostate, bone and ovarian cancer cells. Mediates cancer cell cytotoxicity in an HLA-independent manner. Has no reactivity to healthy cells even stressed or infected by bacteria (PubMed:31959982). Antigen recognition initiates TR-CD3 clustering on the cell surface and intracellular activation of LCK that phosphorylates the ITAM motifs of CD3G, CD3D, CD3E and CD247 enabling the recruitment of ZAP70. In turn, ZAP70 phosphorylates LAT, which recruits numerous signaling molecules to form the LAT signalosome. The LAT signalosome propagates signal branching to three major signaling pathways, the calcium, the mitogen-activated protein kinase (MAPK) kinase and the nuclear factor NF-kappa-B (NF-kB) pathways, leading to the mobilization of transcription factors that are critical for gene expression and essential for T cell differentiation into effector/memory T cells (By similarity).[UniProtKB:P01848][1] TVB65_HUMAN V region of the variable domain of T cell receptor (TR) beta chain that participates in the antigen recognition (PubMed:24600447). Alpha-beta T cell receptors are antigen specific receptors which are essential to the immune response and are present on the cell surface of T lymphocytes. Recognize peptide-major histocompatibility (MH) (pMH) complexes that are displayed by antigen presenting cells (APC), a prerequisite for efficient T cell adaptive immunity against pathogens (PubMed:25493333). Binding of alpha-beta TR to pMH complex initiates TR-CD3 clustering on the cell surface and intracellular activation of LCK that phosphorylates the ITAM motifs of CD3G, CD3D, CD3E and CD247 enabling the recruitment of ZAP70. In turn ZAP70 phosphorylates LAT, which recruits numerous signaling molecules to form the LAT signalosome. The LAT signalosome propagates signal branching to three major signaling pathways, the calcium, the mitogen-activated protein kinase (MAPK) kinase and the nuclear factor NF-kappa-B (NF-kB) pathways, leading to the mobilization of transcription factors that are critical for gene expression and essential for T cell growth and differentiation (PubMed:23524462). The T cell repertoire is generated in the thymus, by V-(D)-J rearrangement. This repertoire is then shaped by intrathymic selection events to generate a peripheral T cell pool of self-MH restricted, non-autoaggressive T cells. Post-thymic interaction of alpha-beta TR with the pMH complexes shapes TR structural and functional avidity (PubMed:15040585).[2] [3] [4] [5] [6] Publication Abstract from PubMedThe T-cell receptor (TCR) initiates T-lymphocyte activation, but mechanistic questions remain( 1-4 ). Here, we present cryogenic electron microscopy structures for the unliganded and human leukocyte antigen (HLA)-bound human TCR-CD3 complex in nanodiscs that provide a native-like lipid environment. Distinct from the "open and extended" conformation seen in detergent( 5-8 ), the unliganded TCR-CD3 in nanodiscs adopts two related "closed and compacted" conformations that represent its physiologic resting state in vivo . By contrast, the HLA-bound complex adopts the open and extended conformation, and conformation-locking disulfide mutants show that ectodomain opening is necessary for maximal ligand-dependent T-cell activation. Together, these results reveal allosteric conformational change during TCR activation and highlight the importance of native-like lipid environments for membrane protein structure determination. The resting and ligand-bound states of the membrane-embedded human T-cell receptor-CD3 complex.,Notti RQ, Yi F, Heissel S, Bush MW, Molvi Z, Das P, Molina H, Klebanoff CA, Walz T bioRxiv [Preprint]. 2024 Sep 20:2023.08.22.554360. doi: , 10.1101/2023.08.22.554360. PMID:37662363[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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