Wataru Shihoya

Endothelin receptors (ET_A and ET_B) are class A GPCRs activated by vasoactive peptide endothelins, and are involved in blood pressure regulation. ET_B-selective signalling induces vasorelaxation, and thus selective ET_B agonists are expected to be utilized for improved anti-tumour drug delivery and neuroprotection. Here, we report the crystal structures of human ET_B receptor in complex with ET_B-selective agonist, endothelin-3 and an

Sarafotoxins (SRTXs) are endothelin-like peptides extracted from snake venom. SRTXs stimulate the endothelin ET_A and ET_B receptors and enhance vasoconstriction, followed by left ventricular dysfunction and bronchoconstriction. SRTXs include four major isopeptides, S6a-d, with different subtype selectivities. Here, we report the crystal structure of the human ET_B receptor in complex with the non-selective sarafotoxin S6b at 3.0 Å resolution. This structure reveals

G-protein-coupled receptors (GPCRs) constitute a prominent superfamily in humans and are categorized into six classes (A-F) that play indispensable roles in cellular communication and therapeutics. Nonetheless, their structural comprehension has been limited by challenges in high-resolution data acquisition. This review highlights the transformative impact of cryogenic electron microscopy (cryo-EM) on the structural determinations of GPCR-G-protein complexes. Specific technologies, such as nanob

Endothelins and their receptors, type A (ETA) and type B (ETB), modulate vital cellular processes, including growth, survival, invasion and angiogenesis, through multiple G proteins. This review highlights the structural determinations of these receptors by X-ray crystallography and cryo-electron microscopy, and their activation mechanisms by endothelins. Explorations of the conformational changes upon receptor activation have provided insights into the unique G-protein coupling feature of the e

The β₃-adrenergic receptor (β₃AR) is the most essential drug target for overactive bladder and has therapeutic potentials for the treatments of type 2 diabetes and obesity. Here, we report the cryo-electron microscopy structures of the β₃AR-G_s signaling complexes with the selective agonist, solabegron and the nonselective agonist, isoproterenol. Comparison of the isoproterenol-, mirabegron-, and solabegron-bound β₃AR structures revealed that

Microbial rhodopsins comprise an opsin protein with seven transmembrane helices and a retinal as the chromophore. An all-trans retinal is covalently bonded to a lysine residue through the retinal Schiff base (RSB) and stabilized by a negatively charged counterion. The distance between the RSB and counterion is closely related to the light energy absorption. However, in heliorhodopsin-48C12 (HeR-48C12), while E107 acts as the counterion, E107D mutation exhibits an identical absorption spectrum to

Abstract Pyroglutamylated RF amide peptide (QRFP) is a type of peptide hormone with a C-terminal RF-amide motif. QRFP selectively activates class-A categorized GPCR, GPR103 to exert various physiological functions such as energy metabolism and appetite regulation. Here, we report the cryo-electron microscopy structure of the QRFP-GPR103-G q complex at 3.3 Å resolution. Unlike class-A GPCR, QRFP adopts an extended structure baring no secondary structure, with its N-terminal and C-terminal sides r

Abstract Rhodopsin phosphodiesterase (Rh-PDE) is an enzyme rhodopsin belonging to a recently discovered class of microbial rhodopsins with light-dependent enzymatic activity. Rh-PDE consists of the N-terminal rhodopsin domain and C-terminal phosphodiesterase (PDE) domain, connected by 76-residue linker, and hydrolyzes both cAMP and cGMP in a light-dependent manner. Thus, Rh-PDE has potential for the optogenetic manipulation of cyclic nucleotide concentrations, as a complementary tool to rhodopsi

Abstract Endothelin receptors (ET A and ET B ) are G-protein coupled receptors activated by endothelin-1 and are involved in blood pressure regulation. IRL2500 is a peptide-mimetic of the C-terminal tripeptide of endothelin-1, and has been characterized as a potent ET B -selective antagonist, which has preventive effects against brain edema. Here, we report the crystal structure of the human ET B receptor in complex with IRL2500 at 2.7 A-resolution. The structure revealed the different binding m

Channelrhodopsins are microbial light-gated ion channels that can control the firing of neurons in response to light. Among several cation channelrhodopsins identified in Guillardia theta (GtCCRs), GtCCR4 has higher light sensitivity than typical channelrhodopsins. Furthermore, GtCCR4 shows superior properties as an optogenetic tool, such as minimal desensitization. Our structural analyses of GtCCR2 and GtCCR4 revealed that GtCCR4 has an outwardly bent transmembrane helix, resembling the conform