title: Evidence that prokineticin receptor 2 exists as a dimer in vivo.
abstract: Prokineticins are proteins that regulate diverse biological processes including gastrointestinal motility, angiogenesis, circadian rhythm, and innate immune response. Prokineticins bind two closed related G-protein coupled receptors (GPCRs), PKR1 and PKR2. In general, these receptors act as molecular switches to relay activation to heterotrimeric G-proteins and a growing body of evidence points to the fact that GPCRs exist as homo- or heterodimers. We show here by Western-blot analysis that PKR2 has a dimeric structure in neutrophils. By heterologous expression of PKR2 in Saccharomyces cerevisiae, we examined the mechanisms of intermolecular interaction of PKR2 dimerization. The potential involvement of three types of mechanisms was investigated: coiled-coil, disulfide bridges, and hydrophobic interactions between transmembrane domains. Characterization of differently deleted or site-directed PKR2 mutants suggests that dimerization proceeds through interactions between transmembrane domains. We demonstrate that co-expressing binding-deficient and signaling-deficient forms of PKR2 can re-establish receptor functionality, possibly through a domain-swapping mechanism.
authors.affiliation: Dipartimento di Scienze Biochimiche 'A. Rossi Fanelli', Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Marsango
authors.forename: Maria Carmela
authors.initials: MC
authors.lastname: Bonaccorsi di Patti
authors.forename: Donatella
authors.initials: D
authors.lastname: Barra
authors.forename: Rossella
authors.initials: R
authors.lastname: Miele
mesh_terms: D019943:Amino Acid Substitution; D019281:Dimerization; D006801:Humans; D009154:Mutation; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018000:Receptors, Peptide / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism
chemical_list: C470838:PROKR2 protein, human; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D011994:Recombinant Proteins