LEAP2 Impairs the Capability of the Growth Hormone Secretagogue Receptor to Regulate the Dopamine 2 Receptor Signaling

• Autores: Mustafá, Emilio Román; Cordisco Gonzalez, Santiago; Damian, Marjorie; Cantel, Sonia; Denoyelle, Severine; Wagner, Renaud; Schiöth, Helgi B.; Fehrentz, Jean Alain; Banères, Jean Louis; Perelló, Mario Carlos; Raingo, Jesica
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Biología; Bioquímica; GPCR; Heterodimerization; Cav2.2; Ghrelin receptor; Dopamine receptor; Constitutive activity
• Institución: Universidad Nacional de La Plata

The growth hormone secretagogue receptor (GHSR) signals in response to ghrelin, but also acts via ligand-independent mechanisms that include either constitutive activation or interaction with other G protein-coupled receptors, such as the dopamine 2 receptor (D2R). A key target of GHSR in neurons is voltage-gated calcium channels type 2.2 (CaV2.2). Recently, the liver-expressed antimicrobial peptide 2 (LEAP2) was recognized as a novel GHSR ligand, but the mechanism of action of LEAP2 on GHSR is not well understood. Here, we investigated the role of LEAP2 on the canonical and non-canonical modes of action of GHSR on CaV2.2 function. Using a heterologous expression system and patch-clamp recordings, we found that LEAP2 impairs the reduction of CaV2.2 currents induced by ghrelin-evoked and constitutive GHSR activities, acting as a GHSR antagonist and inverse agonist, respectively. We also found that LEAP2 prevents GHSR from modulating the effects of D2R signaling on CaV2.2 currents, and that the GHSRbinding N-terminal region LEAP2 underlies these effects. Using purified labeled receptors assembled into lipid nanodiscs and Forster Resonance Energy Transfer (FRET) assessments, we found that the N-terminal region of LEAP2 stabilizes an inactive conformation of GHSR that is dissociated from Gq protein and, consequently, reverses the effect of GHSR on D2R-dependent Gi activation. Thus, our results provide critical molecular insights into the mechanism mediating LEAP2 modulation of GHSR.
Instituto Multidisciplinario de Biología Celular