8itm | pdb_00008itm

Cryo-EM structure of GIPR splice variant 2 (SV2) in complex with Gs protein

spinqualitylabelsall models 8itm, resolution 3.13Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8itm is a 5 chain structure with sequence from Bos taurus, Homo sapiens, Rattus norvegicus and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.13Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function GIPR_HUMAN This is a receptor for GIP. The activity of this receptor is mediated by G proteins which activate adenylyl cyclase. Publication Abstract from PubMed Glucose-dependent insulinotropic polypeptide receptor (GIPR) is a potential drug target for metabolic disorders. It works with glucagon-like peptide-1 receptor and glucagon receptor in humans to maintain glucose homeostasis. Unlike the other two receptors, GIPR has at least 13 reported splice variants (SVs), more than half of which have sequence variations at either C or N terminus. To explore their roles in endogenous peptide-mediated GIPR signaling, we determined the cryoelectron microscopy (cryo-EM) structures of the two N terminus-altered SVs (referred as GIPR-202 and GIPR-209 in the Ensembl database, SV1 and SV2 here, respectively) and investigated the outcome of coexpressing each of them in question with GIPR in HEK293T cells with respect to ligand binding, receptor expression, cAMP (adenosine 3,5-cyclic monophosphate) accumulation, beta-arrestin recruitment, and cell surface localization. It was found that while both N terminus-altered SVs of GIPR neither bound to the hormone nor elicited signal transduction per se, they suppressed ligand binding and cAMP accumulation of GIPR. Meanwhile, SV1 reduced GIPR-mediated beta-arrestin 2 responses. The cryo-EM structures of SV1 and SV2 showed that they reorganized the extracellular halves of transmembrane helices 1, 6, and 7 and extracellular loops 2 and 3 to adopt a ligand-binding pocket-occupied conformation, thereby losing binding ability to the peptide. The results suggest a form of signal bias that is constitutive and ligand-independent, thus expanding our knowledge of biased signaling beyond pharmacological manipulation (i.e., ligand specific) as well as constitutive and ligand-independent (e.g., SV1 of the growth hormone-releasing hormone receptor). Molecular basis of signal transduction mediated by the human GIPR splice variants.,Zhao F, Hang K, Zhou Q, Shao L, Li H, Li W, Lin S, Dai A, Cai X, Liu Y, Xu Y, Feng W, Yang D, Wang MW Proc Natl Acad Sci U S A. 2023 Oct 10;120(41):e2306145120. doi: , 10.1073/pnas.2306145120. Epub 2023 Oct 4. PMID:37792509 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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