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Open data
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Basic information
| Entry | Database: PDB / ID: 9kt9 | ||||||
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| Title | Cryo-EM structure of HCA1-Gi complex with 3,5-DHBA | ||||||
Components |
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Keywords | SIGNALING PROTEIN/IMMUNE SYSTEM / G-protein-coupled receptors / Hydroxycarboxylic acid receptors / cryo-EM / SIGNALING PROTEIN / SIGNALING PROTEIN-IMMUNE SYSTEM complex | ||||||
| Function / homology | Function and homology informationHydroxycarboxylic acid-binding receptors / negative regulation of lipid catabolic process / adenylate cyclase inhibitor activity / positive regulation of protein localization to cell cortex / T cell migration / Adenylate cyclase inhibitory pathway / D2 dopamine receptor binding / response to prostaglandin E / G protein-coupled serotonin receptor binding / adenylate cyclase regulator activity ...Hydroxycarboxylic acid-binding receptors / negative regulation of lipid catabolic process / adenylate cyclase inhibitor activity / positive regulation of protein localization to cell cortex / T cell migration / Adenylate cyclase inhibitory pathway / D2 dopamine receptor binding / response to prostaglandin E / G protein-coupled serotonin receptor binding / adenylate cyclase regulator activity / adenylate cyclase-inhibiting serotonin receptor signaling pathway / cellular response to forskolin / regulation of mitotic spindle organization / Regulation of insulin secretion / positive regulation of cholesterol biosynthetic process / negative regulation of insulin secretion / G protein-coupled receptor binding / response to peptide hormone / G protein-coupled receptor activity / adenylate cyclase-inhibiting G protein-coupled receptor signaling pathway / adenylate cyclase-modulating G protein-coupled receptor signaling pathway / centriolar satellite / G-protein beta/gamma-subunit complex binding / Olfactory Signaling Pathway / Activation of the phototransduction cascade / G beta:gamma signalling through PLC beta / Presynaptic function of Kainate receptors / Thromboxane signalling through TP receptor / G protein-coupled acetylcholine receptor signaling pathway / Activation of G protein gated Potassium channels / Inhibition of voltage gated Ca2+ channels via Gbeta/gamma subunits / G-protein activation / G beta:gamma signalling through CDC42 / Prostacyclin signalling through prostacyclin receptor / Glucagon signaling in metabolic regulation / G beta:gamma signalling through BTK / Synthesis, secretion, and inactivation of Glucagon-like Peptide-1 (GLP-1) / ADP signalling through P2Y purinoceptor 12 / photoreceptor disc membrane / Sensory perception of sweet, bitter, and umami (glutamate) taste / Glucagon-type ligand receptors / GDP binding / Adrenaline,noradrenaline inhibits insulin secretion / Vasopressin regulates renal water homeostasis via Aquaporins / Glucagon-like Peptide-1 (GLP1) regulates insulin secretion / G alpha (z) signalling events / ADP signalling through P2Y purinoceptor 1 / cellular response to catecholamine stimulus / ADORA2B mediated anti-inflammatory cytokines production / G beta:gamma signalling through PI3Kgamma / adenylate cyclase-activating dopamine receptor signaling pathway / Cooperation of PDCL (PhLP1) and TRiC/CCT in G-protein beta folding / GPER1 signaling / G-protein beta-subunit binding / cellular response to prostaglandin E stimulus / heterotrimeric G-protein complex / Inactivation, recovery and regulation of the phototransduction cascade / G alpha (12/13) signalling events / extracellular vesicle / sensory perception of taste / Thrombin signalling through proteinase activated receptors (PARs) / signaling receptor complex adaptor activity / G protein activity / retina development in camera-type eye / GTPase binding / Ca2+ pathway / fibroblast proliferation / midbody / cell cortex / High laminar flow shear stress activates signaling by PIEZO1 and PECAM1:CDH5:KDR in endothelial cells / G alpha (i) signalling events / G alpha (s) signalling events / phospholipase C-activating G protein-coupled receptor signaling pathway / G alpha (q) signalling events / Hydrolases; Acting on acid anhydrides; Acting on GTP to facilitate cellular and subcellular movement / Ras protein signal transduction / Extra-nuclear estrogen signaling / cell population proliferation / ciliary basal body / G protein-coupled receptor signaling pathway / lysosomal membrane / cell division / GTPase activity / synapse / centrosome / GTP binding / protein-containing complex binding / nucleolus / magnesium ion binding / Golgi apparatus / signal transduction / extracellular exosome / nucleoplasm / membrane / plasma membrane / cytosol / cytoplasm Similarity search - Function | ||||||
| Biological species | Homo sapiens (human) | ||||||
| Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.7 Å | ||||||
Authors | Wu, S. | ||||||
| Funding support | China, 1items
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Citation | Journal: J Med Chem / Year: 2025Title: Insights into the Activation Mechanism of HCA1, HCA2, and HCA3. Authors: Jiening Wang / Yuxia Qian / Zhen Han / Yize Wang / Yanru Liu / Jie Li / Qingmiao Duanmu / Sheng Ye / Anna Qiao / Shan Wu / ![]() Abstract: Hydroxy-carboxylic acid receptors HCA1, HCA2, and HCA3 can be activated by important intermediates of energy metabolism. Despite the research focusing on HCA2, its clinical application has been ...Hydroxy-carboxylic acid receptors HCA1, HCA2, and HCA3 can be activated by important intermediates of energy metabolism. Despite the research focusing on HCA2, its clinical application has been limited by adverse effects. Therefore, the role of HCA1 as a promising target for the treatment of lipolysis warrants further exploration. As HCAs exhibit high similarity when activated with diverse selective agonists, a conserved yet unique activation mechanism for HCAs remains undisclosed. Herein, we unveil the cryo-electron microscopy structures of the 3,5-DHBA-HCA1-Gi signaling complex, the acifran- and MK6892-bound HCA2-Gi signaling complexes, and the acifran-HCA3-Gi signaling complex. Comparative analysis across HCAs reveals key residues in HCA1 contributing to the stabilization of the ligand-binding pocket. Furthermore, chimeric complexes and mutational analyses identify residues that are pivotal for HCA2 and HCA3 selectivity. Our findings elucidate critical structural insights into the mechanisms of ligand recognition and activation within HCA1 and broaden our comprehension of ligand specificity binding across the HCA family. | ||||||
| History |
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Structure visualization
| Structure viewer | Molecule: Molmil Jmol/JSmol |
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Downloads & links
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Download
| PDBx/mmCIF format | 9kt9.cif.gz | 213.9 KB | Display | PDBx/mmCIF format |
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| PDB format | pdb9kt9.ent.gz | 165.9 KB | Display | PDB format |
| PDBx/mmJSON format | 9kt9.json.gz | Tree view | PDBx/mmJSON format | |
| Others | Other downloads |
-Validation report
| Arichive directory | https://data.pdbj.org/pub/pdb/validation_reports/kt/9kt9 ftp://data.pdbj.org/pub/pdb/validation_reports/kt/9kt9 | HTTPS FTP |
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-Related structure data
| Related structure data | ![]() 62560MC ![]() 9kt6C ![]() 9kt7C ![]() 9kt8C M: map data used to model this data C: citing same article ( |
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| Similar structure data | Similarity search - Function & homology F&H Search |
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Links
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Assembly
| Deposited unit | ![]()
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| 1 |
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Components
-Guanine nucleotide-binding protein ... , 3 types, 3 molecules ABC
| #1: Protein | Mass: 40414.047 Da / Num. of mol.: 1 / Mutation: S47N,G203A,E245A,A326S Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: GNAI1 / Production host: ![]() |
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| #2: Protein | Mass: 37413.863 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: GNB1 / Production host: ![]() |
| #3: Protein | Mass: 7861.143 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: GNG2 / Production host: ![]() |
-Antibody / Protein / Non-polymers , 3 types, 3 molecules ER

| #4: Antibody | Mass: 28685.027 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Production host: ![]() |
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| #5: Protein | Mass: 39338.254 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) Homo sapiens (human) / Gene: HCAR1, GPR104, GPR81, HCA1, FKSG80 / Production host: ![]() |
| #6: Chemical | ChemComp-34D / |
-Details
| Has ligand of interest | Y |
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| Has protein modification | Y |
-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: Cryo-EM structure of HCA1-Gi complex with 3,5-DHBA / Type: COMPLEX / Entity ID: #1-#5 / Source: RECOMBINANT |
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| Source (natural) | Organism: Homo sapiens (human) |
| Source (recombinant) | Organism: ![]() |
| Buffer solution | pH: 7.5 |
| Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
| Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
| Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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| Microscopy | Model: TFS KRIOS |
| Electron gun | Electron source: FIELD EMISSION GUN / Accelerating voltage: 300 kV / Illumination mode: FLOOD BEAM |
| Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 1500 nm / Nominal defocus min: 1000 nm |
| Image recording | Electron dose: 54 e/Å2 / Film or detector model: GATAN K3 BIOCONTINUUM (6k x 4k) |
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Processing
| CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
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| 3D reconstruction | Resolution: 2.7 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 918047 / Symmetry type: POINT | ||||||||||||||||||||||||
| Refine LS restraints |
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About Yorodumi




Homo sapiens (human)
China, 1items
Citation






PDBj
































FIELD EMISSION GUN