title: Biochemical properties of gastrokine-1 purified from chicken gizzard smooth muscle.
abstract: The potential role and function of gastrokine-1 (GNK1) in smooth muscle cells is investigated in this work by first establishing a preparative protocol to obtain this native protein from freshly dissected chicken gizzard. Some unexpected biochemical properties of gastrokine-1 were deduced by producing specific polyclonal antibody against the purified protein. We focused on the F-actin interaction with gastrokine-1 and the potential role and function in smooth muscle contractile properties.
  
  
  BACKGROUND
  GNK1 is thought to provide mucosal protection in the superficial gastric epithelium. However, the actual role of gastrokine-1 with regards to its known decreased expression in gastric cancer is still unknown. Recently, trefoil factors (TFF) were reported to have important roles in gastric epithelial regeneration and cell turnover, and could be involved in GNK1 interactions. The aim of this study was to evaluate the role and function of GNK1 in smooth muscle cells.
  
  
  RESULTS
  From fresh chicken gizzard smooth muscle, an original purification procedure was used to purify a heat soluble 20 kDa protein that was sequenced and found to correspond to the gastrokine-1 protein sequence containing one BRICHOS domain and at least two or possibly three transmembrane regions. The purified protein was used to produce polyclonal antibody and highlighted the smooth muscle cell distribution and F-actin association of GNK1 through a few different methods.
  
  
  CONCLUSIONS
  Altogether our data illustrate a broader distribution of gastrokine-1 in smooth muscle than only in the gastrointestinal epithelium, and the specific interaction with F-actin highlights and suggests a new role and function of GNK1 within smooth muscle cells. A potential role via TFF interaction in cell-cell adhesion and assembly of actin stress fibres is discussed.
authors.affiliation: INSERM ERI 25 Muscle et Pathologies, Université Montpellier 1, EA 4202, CHU Arnaud de Villeneuve, Montpellier, France.
authors.forename: Karim
authors.initials: K
authors.lastname: Hnia
authors.forename: Cécile
authors.initials: C
authors.lastname: Notarnicola
authors.forename: Pascal
authors.initials: P
authors.lastname: de Santa Barbara
authors.forename: Gérald
authors.initials: G
authors.lastname: Hugon
authors.forename: François
authors.initials: F
authors.lastname: Rivier
authors.forename: Dalila
authors.initials: D
authors.lastname: Laoudj-Chenivesse
authors.forename: Dominique
authors.initials: D
authors.lastname: Mornet
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D030161:Avian Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D002645:Chickens / Q000378:metabolism*; D005895:Gizzard, Avian / Q000737:chemistry* / Q000378:metabolism; D007150:Immunohistochemistry; D009124:Muscle Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D009130:Muscle, Smooth / Q000737:chemistry* / Q000378:metabolism*; D014335:Tropomyosin / Q000378:metabolism
chemical_list: D000199:Actins; D030161:Avian Proteins; D009124:Muscle Proteins; D014335:Tropomyosin