scholarly journals Constitutive signal bias mediated by the human GHRHR splice variant 1

2021 ◽  
Author(s):  
Zhaotong Cong ◽  
Fulai Zhou ◽  
Chao Zhang ◽  
Xinyu Zou ◽  
Huibing Zhang ◽  
...  

Alternative splicing of G protein-coupled receptors has been observed, but their functions are largely unknown. Here, we report that a splice variant (SV1) of the human growth hormone releasing hormone receptor (GHRHR) is capable of transducing biased signal. Differing only at the receptor N terminus, GHRHR predominantly activates Gs while SV1 selectively couples to β-arrestins. Based on the cryo-electron microscopy structures of SV1 in the apo state or in complex with the Gs protein, molecular dynamics simulations reveal that the N termini of GHRHR and SV1 differentiate the downstream signaling pathways, Gs vs. β-arrestins. Suggested by mutagenesis and functional studies, it appears that GHRH-elicited signal bias towards β-arrestin recruitment is constitutively mediated by SV1. The level of SV1 expression in prostate cancer cells is also positively correlated with ERK1/2 phosphorylation but negatively correlated with cAMP response. Our findings imply that constitutive signal bias may be a mechanism that ensures cancer cell proliferation.

2021 ◽  
Vol 118 (40) ◽  
pp. e2106606118
Author(s):  
Zhaotong Cong ◽  
Fulai Zhou ◽  
Chao Zhang ◽  
Xinyu Zou ◽  
Huibing Zhang ◽  
...  

Alternative splicing of G protein–coupled receptors has been observed, but their functions are largely unknown. Here, we report that a splice variant (SV1) of the human growth hormone–releasing hormone receptor (GHRHR) is capable of transducing biased signal. Differing only at the receptor N terminus, GHRHR predominantly activates Gs while SV1 selectively couples to β-arrestins. Based on the cryogenic electron microscopy structures of SV1 in the apo state or GHRH-bound state in complex with the Gs protein, molecular dynamics simulations reveal that the N termini of GHRHR and SV1 differentiate the downstream signaling pathways, Gs versus β-arrestins. As suggested by mutagenesis and functional studies, it appears that GHRH-elicited signal bias toward β-arrestin recruitment is constitutively mediated by SV1. The level of SV1 expression in prostate cancer cells is also positively correlated with ERK1/2 phosphorylation but negatively correlated with cAMP response. Our findings imply that constitutive signal bias may be a mechanism that ensures cancer cell proliferation.


2007 ◽  
Vol 129 (33) ◽  
pp. 10126-10132 ◽  
Author(s):  
Xavier Periole ◽  
Thomas Huber ◽  
Siewert-Jan Marrink ◽  
Thomas P. Sakmar

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3798 ◽  
Author(s):  
Emmanuel Bresso ◽  
Diana Fernandez ◽  
Deisy X. Amora ◽  
Philippe Noel ◽  
Anne-Sophie Petitot ◽  
...  

Root-knot nematodes (RKN), from the Meloidogyne genus, have a worldwide distribution and cause severe economic damage to many life-sustaining crops. Because of their lack of specificity and danger to the environment, most chemical nematicides have been banned from use. Thus, there is a great need for new and safe compounds to control RKN. Such research involves identifying beforehand the nematode proteins essential to the invasion. Since G protein-coupled receptors GPCRs are the target of a large number of drugs, we have focused our research on the identification of putative nematode GPCRs such as those capable of controlling the movement of the parasite towards (or within) its host. A datamining procedure applied to the genome of Meloidogyne incognita allowed us to identify a GPCR, belonging to the neuropeptide GPCR family that can serve as a target to carry out a virtual screening campaign. We reconstructed a 3D model of this receptor by homology modeling and validated it through extensive molecular dynamics simulations. This model was used for large scale molecular dockings which produced a filtered limited set of putative antagonists for this GPCR. Preliminary experiments using these selected molecules allowed the identification of an active compound, namely C260-2124, from the ChemDiv provider, which can serve as a starting point for further investigations.


2022 ◽  
Author(s):  
Michael J. Robertson ◽  
Georgios Skiniotis

G protein-coupled receptors (GPCRs) and other membrane proteins are valuable drug targets, and their dynamic nature makes them attractive systems for study with molecular dynamics simulations and free energy approaches. Here, we report the development, implementation, and validation of OPLS-AA/M force field parameters to enable simulations of these systems. These efforts include the introduction of post-translational modifications including lipidations and phosphorylation. We also modify previously reported parameters for lipids to be more consistent with the OPLS-AA force field standard and extend their coverage. These new parameters are validated on a variety of test systems, with the results compared to high-level quantum mechanics calculations, experimental data, and simulations with CHARMM36m where relevant. The results demonstrate that the new parameters reliably reproduce the behavior of membrane protein systems.


2019 ◽  
Vol 20 (13) ◽  
pp. 3207 ◽  
Author(s):  
Hidetoshi Komatsu ◽  
Mamoru Fukuchi ◽  
Yugo Habata

Tremendous advances have been made recently in the identification of genes and signaling pathways associated with the risks for psychiatric disorders such as schizophrenia and bipolar disorder. However, there has been a marked reduction in the pipeline for the development of new psychiatric drugs worldwide, mainly due to the complex causes that underlie these disorders. G-protein coupled receptors (GPCRs) are the most common targets of antipsychotics such as quetiapine and aripiprazole, and play pivotal roles in controlling brain function by regulating multiple downstream signaling pathways. Progress in our understanding of GPCR signaling has opened new possibilities for selective drug development. A key finding has been provided by the concept of biased ligands, which modulate some, but not all, of a given receptor’s downstream signaling pathways. Application of this concept raises the possibility that the biased ligands can provide therapeutically desirable outcomes with fewer side effects. Instead, this application will require a detailed understanding of the mode of action of antipsychotics that drive distinct pharmacologies. We review our current understanding of the mechanistic bases for multiple signaling modes by antipsychotics and the potential of the biased modulators to treat mental disorders.


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