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Open data
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Basic information
Entry | Database: PDB / ID: 6eny | ||||||||||||
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Title | Structure of the human PLC editing module | ||||||||||||
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![]() | IMMUNE SYSTEM / adaptive immunity / antigen processing / chaperone / MHC class I | ||||||||||||
Function / homology | ![]() MHC class Ib protein complex assembly / peptide antigen stabilization / Tapasin-ERp57 complex / Calnexin/calreticulin cycle / response to biphenyl / MHC class I protein complex binding / TAP2 binding / TAP1 binding / cytolytic granule / positive regulation of dendritic cell chemotaxis ...MHC class Ib protein complex assembly / peptide antigen stabilization / Tapasin-ERp57 complex / Calnexin/calreticulin cycle / response to biphenyl / MHC class I protein complex binding / TAP2 binding / TAP1 binding / cytolytic granule / positive regulation of dendritic cell chemotaxis / protein disulfide-isomerase / ATF6 (ATF6-alpha) activates chaperone genes / Assembly of Viral Components at the Budding Site / cortical granule / negative regulation of trophoblast cell migration / nuclear receptor-mediated glucocorticoid signaling pathway / cellular response to electrical stimulus / complement component C1q complex binding / response to peptide / regulation of meiotic nuclear division / negative regulation of retinoic acid receptor signaling pathway / sequestering of calcium ion / endoplasmic reticulum quality control compartment / protein folding in endoplasmic reticulum / sarcoplasmic reticulum lumen / response to glycoside / disulfide oxidoreductase activity / hormone binding / negative regulation of intracellular steroid hormone receptor signaling pathway / regulation of protein complex stability / nuclear export signal receptor activity / cardiac muscle cell differentiation / phospholipase C activity / retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum / cellular response to interleukin-7 / positive regulation of extrinsic apoptotic signaling pathway / cortical actin cytoskeleton organization / positive regulation of memory T cell activation / T cell mediated cytotoxicity directed against tumor cell target / TAP complex binding / Scavenging by Class A Receptors / Golgi medial cisterna / positive regulation of CD8-positive, alpha-beta T cell activation / CD8-positive, alpha-beta T cell activation / positive regulation of CD8-positive, alpha-beta T cell proliferation / nuclear androgen receptor binding / Scavenging by Class F Receptors / CD8 receptor binding / cellular response to lithium ion / protein disulfide isomerase activity / antigen processing and presentation of exogenous peptide antigen via MHC class I / beta-2-microglobulin binding / MHC class I protein binding / response to testosterone / endoplasmic reticulum exit site / antigen processing and presentation of endogenous peptide antigen via MHC class I via ER pathway, TAP-dependent / TAP binding / molecular sequestering activity / protection from natural killer cell mediated cytotoxicity / protein-disulfide reductase activity / antigen processing and presentation of endogenous peptide antigen via MHC class I via ER pathway, TAP-independent / antigen processing and presentation of endogenous peptide antigen via MHC class Ib / negative regulation of neuron differentiation / protein localization to nucleus / smooth endoplasmic reticulum / detection of bacterium / T cell receptor binding / positive regulation of phagocytosis / phagocytic vesicle / extrinsic apoptotic signaling pathway / positive regulation of cell cycle / ERAD pathway / positive regulation of substrate adhesion-dependent cell spreading / positive regulation of endothelial cell migration / endoplasmic reticulum-Golgi intermediate compartment membrane / endocytic vesicle lumen / protein folding chaperone / protein maturation / peptide binding / response to endoplasmic reticulum stress / protein export from nucleus / : / : / acrosomal vesicle / positive regulation of receptor binding / early endosome lumen / Nef mediated downregulation of MHC class I complex cell surface expression / negative regulation of receptor binding / DAP12 interactions / cellular response to iron ion / lumenal side of endoplasmic reticulum membrane / Endosomal/Vacuolar pathway / Antigen Presentation: Folding, assembly and peptide loading of class I MHC / peptide antigen assembly with MHC class II protein complex / cellular response to iron(III) ion / antigen processing and presentation of exogenous protein antigen via MHC class Ib, TAP-dependent / MHC class II protein complex / negative regulation of forebrain neuron differentiation / ER to Golgi transport vesicle membrane / peptide antigen assembly with MHC class I protein complex Similarity search - Function | ||||||||||||
Biological species | ![]() | ||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 5.8 Å | ||||||||||||
![]() | Trowitzsch, S. / Januliene, D. / Blees, A. / Moeller, A. / Tampe, R. | ||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Structure of the human MHC-I peptide-loading complex. Authors: Andreas Blees / Dovile Januliene / Tommy Hofmann / Nicole Koller / Carla Schmidt / Simon Trowitzsch / Arne Moeller / Robert Tampé / ![]() Abstract: The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum that is essential for establishing a hierarchical immune response. The PLC coordinates ...The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum that is essential for establishing a hierarchical immune response. The PLC coordinates peptide translocation into the endoplasmic reticulum with loading and editing of major histocompatibility complex class I (MHC-I) molecules. After final proofreading in the PLC, stable peptide-MHC-I complexes are released to the cell surface to evoke a T-cell response against infected or malignant cells. Sampling of different MHC-I allomorphs requires the precise coordination of seven different subunits in a single macromolecular assembly, including the transporter associated with antigen processing (TAP1 and TAP2, jointly referred to as TAP), the oxidoreductase ERp57, the MHC-I heterodimer, and the chaperones tapasin and calreticulin. The molecular organization of and mechanistic events that take place in the PLC are unknown owing to the heterogeneous composition and intrinsically dynamic nature of the complex. Here, we isolate human PLC from Burkitt's lymphoma cells using an engineered viral inhibitor as bait and determine the structure of native PLC by electron cryo-microscopy. Two endoplasmic reticulum-resident editing modules composed of tapasin, calreticulin, ERp57, and MHC-I are centred around TAP in a pseudo-symmetric orientation. A multivalent chaperone network within and across the editing modules establishes the proofreading function at two lateral binding platforms for MHC-I molecules. The lectin-like domain of calreticulin senses the MHC-I glycan, whereas the P domain reaches over the MHC-I peptide-binding pocket towards ERp57. This arrangement allows tapasin to facilitate peptide editing by clamping MHC-I. The translocation pathway of TAP opens out into a large endoplasmic reticulum lumenal cavity, confined by the membrane entry points of tapasin and MHC-I. Two lateral windows channel the antigenic peptides to MHC-I. Structures of PLC captured at distinct assembly states provide mechanistic insight into the recruitment and release of MHC-I. Our work defines the molecular symbiosis of an ABC transporter and an endoplasmic reticulum chaperone network in MHC-I assembly and provides insight into the onset of the adaptive immune response. | ||||||||||||
History |
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Structure visualization
Movie |
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Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 257.1 KB | Display | ![]() |
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PDB format | ![]() | 168 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 3906MC ![]() 3904C ![]() 3905C M: map data used to model this data C: citing same article ( |
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Similar structure data |
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Links
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Assembly
Deposited unit | ![]()
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Components
-Protein , 5 types, 5 molecules BCDFG
#1: Protein | Mass: 11748.160 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
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#2: Protein | Mass: 45761.184 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
#3: Protein | Mass: 54341.102 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
#4: Protein | Mass: 38363.535 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
#5: Protein | Mass: 46507.145 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() |
-Sugars , 2 types, 2 molecules
#6: Polysaccharide | 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose Source method: isolated from a genetically manipulated source |
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#7: Polysaccharide | beta-D-glucopyranose-(1-3)-alpha-D-mannopyranose-(1-2)-alpha-D-mannopyranose-(1-2)-alpha-D-mannopyranose Type: oligosaccharide / Mass: 666.578 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source |
-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: Protein Complex / Type: COMPLEX / Entity ID: #1-#5 / Source: NATURAL |
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Molecular weight | Experimental value: NO |
Source (natural) | Organism: ![]() |
Buffer solution | pH: 7.5 |
Specimen | Conc.: 2 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Specimen support | Grid type: C-flat-2/2 |
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 277 K |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD |
Image recording | Electron dose: 55 e/Å2 / Detector mode: COUNTING / Film or detector model: GATAN K2 QUANTUM (4k x 4k) |
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Processing
EM software |
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CTF correction | Details: CTF correction was performed internally in Relion and Frealign Type: NONE | ||||||||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 5.8 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 141078 / Symmetry type: POINT | ||||||||||||||||||||||||||||||||||||
Refinement | Highest resolution: 5.8 Å |