title: Structural and functional similarities between osmotin from Nicotiana tabacum seeds and human adiponectin.
abstract: Osmotin, a plant protein, specifically binds a seven transmembrane domain receptor-like protein to exert its biological activity via a RAS2/cAMP signaling pathway. The receptor protein is encoded in the gene ORE20/PHO36 and the mammalian homolog of PHO36 is a receptor for the human hormone adiponectin (ADIPOR1). Moreover it is known that the osmotin domain I can be overlapped to the β-barrel domain of adiponectin. Therefore, these observations and some already existing structural and biological data open a window on a possible use of the osmotin or of its derivative as adiponectin agonist. We have modelled the three-dimensional structure of the adiponectin trimer (ADIPOQ), and two ADIPOR1 and PHO36 receptors. Moreover, we have also modelled the following complexes: ADIPOQ/ADIPOR1, osmotin/PHO36 and osmotin/ADIPOR1. We have then shown the structural determinants of these interactions and their physico-chemical features and analyzed the related interaction residues involved in the formation of the complexes. The stability of the modelled structures and their complexes was always evaluated and controlled by molecular dynamics. On the basis of these results a 9 residues osmotin peptide was selected and its interaction with ADIPOR1 and PHO36 was modelled and analysed in term of energetic stability by molecular dynamics. To confirm in vivo the molecular modelling data, osmotin has been purified from nicotiana tabacum seeds and its nine residues peptide synthesized. We have used cultured human synovial fibroblasts that respond to adiponectin by increasing the expression of IL-6, TNF-alpha and IL-1beta via ADIPOR1. The biological effect on fibroblasts of osmotin and its peptide derivative has been found similar to that of adiponectin confirming the results found in silico.
authors.affiliation: Department of Biochemistry and Biophysics and CRISCEB-(Interdepartmental Research Center for Computational and Biotechnological Sciences), Second University of Naples, Naples, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Miele
authors.forename: Susan
authors.initials: S
authors.lastname: Costantini
authors.forename: Giovanni
authors.initials: G
authors.lastname: Colonna
mesh_terms: D052242:Adiponectin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D000595:Amino Acid Sequence; D002478:Cells, Cultured; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D055503:Protein Multimerization / Q000502:physiology; D054419:Receptors, Adiponectin / Q000737:chemistry / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D012639:Seeds / Q000737:chemistry / Q000378:metabolism; D017385:Sequence Homology; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000737:chemistry / Q000378:metabolism
chemical_list: C499918:ADIPOQ protein, human; C475418:ADIPOR1 protein, human; D052242:Adiponectin; C497767:IZH2 protein, S cerevisiae; D008565:Membrane Proteins; D010940:Plant Proteins; D054419:Receptors, Adiponectin; D029701:Saccharomyces cerevisiae Proteins; C073139:osmotin protein, Nicotiana tabacum