Total synthesis and structure–activity relationship studies of a series of selective G protein inhibitors

Abstract

G proteins are key mediators of G protein-coupled receptor signalling, which facilitates a plethora of important physiological processes. The cyclic depsipeptides YM-254890 and FR900359 are the only known specific inhibitors of the Gq subfamily of G proteins; however, no synthetic route has been reported previously for these complex natural products and they are not easily isolated from natural sources. Here we report the first total synthesis of YM-254890 and FR900359, as well as of two known analogues, YM-385780 and YM-385781. The versatility of the synthetic approach also enabled the design and synthesis of ten analogues, which provided the first structure–activity relationship study for this class of compounds. Pharmacological characterization of all the compounds at Gq-, Gi- and Gs-mediated signalling provided succinct information on the structural requirements for inhibition, and demonstrated that both YM-254890 and FR900359 are highly potent inhibitors of Gq signalling, with FR900359 being the most potent. These natural products and their analogues represent unique tools for explorative studies of G protein inhibition.

The GPRC6A receptor displays constitutive internalization and sorting to the slow recycling pathway

“…FR900359 (40,41). In the functional IP-One assay, the L-Orn-induced response of GPRC6A was completely inhibited by 1 M FR900359 (Fig.…”

Knockin mouse with mutant Gα11 mimics human inherited hypocalcemia and is rescued by pharmacologic inhibitors

“…Based on limited dose response studies (data not shown), mice were injected i.p. with either 0.15 mg/kg of the selective Gα 11/q inhibitor YM-254890 (24), which was diluted in 0.27% DMSO, or an equal volume of 0.27% DMSO as the vehicle control. Blood was taken from the superficial temporal vein at baseline, 4, and 24 hours after injection, and ionized calcium, PTH, and phosphorous were measured as previously described (43).…”

“…NPS 2143 hydrochloride (2-Chloro-6-[ (2R)-3-[[1,1-dimethyl-2-(2-naphthalenyl)ethyl] amino]-2-hydroxypropoxy]-benzonitrile hydrochloride) was obtained from Sigma-Aldrich (catalog SML0362) and dissolved in a 20% aqueous solution of 2-hydroxypropyl-β-cyclodextrin (Sigma-Aldrich, catalog H107) prior to use in in vitro studies, as described (21,25). YM-254890 was synthesized as previously described (24).…”

“…as an inhibitor of ADP-induced platelet aggregation (22). Successful total synthesis has recently been reported (24). X-ray crystallography has shown that YM-254890 bound to Gα q , which is very similar to Gα 11 , interacts with switch 1 and hinders linker flexibility between the GTPase domain and the helical domain of the Gα 11/q protein ( Figure 8D).…”

“…We therefore generated a knockin mouse model of ADH2 with a germline GNA11 c.C178T point mutation (p.Arg60Cys), which was identified in a family affected with ADH2 (10). We report here the phenotypic properties of the mutant mice, as well as their response to treatment with two inhibitors with relevance to the disease; the small molecule calcilytic drug, NPS 2143, which acts as a negative allosteric modulator (NAM) of the CASR and thereby can induce increased PTH secretion (20,21); and the cyclic depsipeptide YM-254890, which acts as a competitive inhibitor of Gα 11/q (22)(23)(24).…”