Yves COMBARNOUS

Abstract Variable fragments from camelid heavy-chain only antibodies (VHH) can stabilize active conformations of G protein-coupled receptors (GPCRs), enabling 3D structural characterization and supporting detailed structure–activity studies by linking receptor conformational states to downstream signaling. When expressed intracellularly, these VHHs have recently proven useful for tracking active GPCRs across subcellular compartments.

Introduction Reproductive cycles in vertebrates are regulated by the hypothalamus. The secretion of gonadotropin releasing hormone (GnRH) stimulates the pituitary gland to release the gonadotropins luteinizing hormone (LH) and follicle stimulating hormone (FSH) (Licht, 1980; Kang et al., 2020). Gonadotropins (GTH) are composed of a common α-subunit, and a unique β-subunit with a biological role specific to each hormone (Aizen et al., 2007a; Aizen et al., 2007b).

Introduction After its isolation and identification in the pineal gland of the cow, in subsequent years melatonin was identified in a wide variety of animals and plants (1–7). The extensive distribution of melatonin, especially in the primitive bacteria (cyanobacteria and α-proteobacteria) indicates that the chemical is an ancient molecule that has been retained throughout the evolution of all organisms (8, 9) (Figure 1).