title: Functional role of the heterodimeric glycoprotein hormone, GPA2/GPB5, and its receptor, LGR1: An invertebrate perspective.
abstract: In vertebrates, follicle-stimulating hormone (FSH), luteinizing hormone (LH), chorionic gonadotropin (CG) and thyroid-stimulating hormone (TSH) are glycoprotein hormones that play central roles in metabolism, reproduction and development. Recently, a novel heterodimeric glycoprotein hormone, called GPA2/GPB5, was discovered in humans; however, contrary to its vertebrate glycoprotein hormone relatives, the physiological role of GPA2/GPB5 has not yet been fully elucidated in any vertebrate or invertebrate. Moreover, it is unclear as to whether GPA2/GPB5 functions as a heterodimer or as individual GPA2 and GPB5 monomers in these organisms. GPA2- and GPB5-like subunits have been identified or predicted in a wide array of animal phyla including the nematodes, chordates, hemichordates, arthropods, molluscs, echinoderms and annelids. So far, molecular studies on transcript expression of the GPA2/GPB5 subunits and its putative receptor, the leucine-rich repeat-containing G protein-coupled receptor 1 (LGR1), suggests this glycoprotein hormone system plays a developmental role and may also function in hydromineral balance in invertebrates. This mini-review summarizes the current state of knowledge on the physiological actions and activity of this evolutionarily ancient heterodimeric glycoprotein hormone with a particular focus on its known functions in the invertebrates.
authors.affiliation: Department of Biology, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Rocco
authors.affiliation: Department of Biology, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada. Electronic address: paluzzi@yorku.ca.
authors.forename: Jean-Paul V
authors.initials: JP
authors.lastname: Paluzzi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007448:Invertebrates / Q000378:metabolism; D014714:Vertebrates / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D005640:Follicle Stimulating Hormone
keywords: Epithelia; Glycoprotein hormone; Heterodimeric glycoprotein hormone; Ionoregulation; Leucine-rich repeat-containing receptor; Osmoregulation; Paracrine; Reproduction; Thyrostimulin