7xmr | pdb_00007xmr
CryoEM structure of the somatostatin receptor 2 (SSTR2) in complex with Gi1 and its endogeneous peptide ligand SST-14
Structural highlights
Function[SSR2_HUMAN] Receptor for somatostatin-14 and -28. This receptor is coupled via pertussis toxin sensitive G proteins to inhibition of adenylyl cyclase. In addition it stimulates phosphotyrosine phosphatase and PLC via pertussis toxin insensitive as well as sensitive G proteins. Inhibits calcium entry by suppressing voltage-dependent calcium channels. Acts as the functionally dominant somatostatin receptor in pancreatic alpha- and beta-cells where it mediates the inhibitory effect of somatostatin-14 on hormone secretion. Inhibits cell growth through enhancement of MAPK1 and MAPK2 phosphorylation and subsequent up-regulation of CDKN1B. Stimulates neuronal migration and axon outgrowth and may participate in neuron development and maturation during brain development. Mediates negative regulation of insulin receptor signaling through PTPN6. Inactivates SSTR3 receptor function following heterodimerization.[1] [2] [3] [4] [5] Publication Abstract from PubMedSomatostatin receptors (SSTRs) play versatile roles in inhibiting the secretion of multiple hormones such as growth hormone and thyroid-stimulating hormone, and thus are considered as targets for treating multiple tumors. Despite great progress made in therapeutic development against this diverse receptor family, drugs that target SSTRs still show limited efficacy with preferential binding affinity and conspicuous side-effects. Here, we report five structures of SSTR2 and SSTR4 in different states, including two crystal structures of SSTR2 in complex with a selective peptide antagonist and a non-peptide agonist, respectively, a cryo-electron microscopy (cryo-EM) structure of Gi1-bound SSTR2 in the presence of the endogenous ligand SST-14, as well as two cryo-EM structures of Gi1-bound SSTR4 in complex with SST-14 and a small-molecule agonist J-2156, respectively. By comparison of the SSTR structures in different states, molecular mechanisms of agonism and antagonism were illustrated. Together with computational and functional analyses, the key determinants responsible for ligand recognition and selectivity of different SSTR subtypes and multiform binding modes of peptide and non-peptide ligands were identified. Insights gained in this study will help uncover ligand selectivity of various SSTRs and accelerate the development of new molecules with better efficacy by targeting SSTRs. Structural insights into ligand recognition and selectivity of somatostatin receptors.,Zhao W, Han S, Qiu N, Feng W, Lu M, Zhang W, Wang M, Zhou Q, Chen S, Xu W, Du J, Chu X, Yi C, Dai A, Hu L, Shen MY, Sun Y, Zhang Q, Ma Y, Zhong W, Yang D, Wang MW, Wu B, Zhao Q Cell Res. 2022 Aug;32(8):761-772. doi: 10.1038/s41422-022-00679-x. Epub 2022 Jun , 23. PMID:35739238[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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