title: Noradrenaline induces binding of Clathrin light chain A to α1-adrenoceptors in the human prostate.
abstract: BACKGROUND
  Binding of clathrins or caveolin to G protein-coupled receptors may induce post-translational modifications of receptor function. Receptor regulation by clathrin requires cofactors ADP-ribosylation factor 6 (ARF6) and adaptin, while dynamin is required for clathrin- and caveolin-dependent mechanisms.
  
  
  OBJECTIVE
  To investigate the expression and α1-adrenoceptor binding of clathrins, caveolin, and their cofactors in the human prostate.
  
  
  METHODS
  Prostate tissue was obtained from radical prostatectomy. Expression of clathrin heavy chain (HC), clathrin light chain A and B (LCA, LCB), caveolin-1, ARF6, β-adaptin, and dynamin-2 was studied by RT-PCR, Western blot, immunohistochemistry, and fluorescence staining. Interaction of α1A-adrenoceptors with clathrins and caveolin-1 was studied by coimmunoprecipitation.
  
  
  RESULTS
  mRNA and protein expression of clathrin HC, LCA, LCB, caveolin-1, dynamin-2, and β-adaptin was detected in prostate tissues of each patient. Immunohistochemistry demonstrated the expression of clathrin HC, LCA, LCB, caveolin, dynamin, and β-adaptin in stromal cells. Immunoreactivity for these proteins colocalized with α-smooth muscle actin and α1A-adrenoceptors in double fluorescence staining. Coimmunoprecipitation demonstrated that α1A-adrenoceptors in prostate tissue interact with clathrin HC and LCB under resting conditions, but not with caveolin-1. Stimulation of prostate tissues with noradrenaline (30 µM) in vitro induced binding of clathrin LCA to α1A-adrenoceptors.
  
  
  CONCLUSIONS
  The prostatic α1-adrenoceptor population is at least partially bound to clathrin HC and LCB. Upon receptor activation, prostate α1A-adrenoceptors bind clathrin LCA. This points to a new concept of post-translational α1-adrenoceptor regulation in the prostate, which includes receptor interaction with accessory binding partners.
authors: Department of Urology, Ludwig-Maximilians University, Munich, Germany.
authors: Martin
authors: M
authors: Hennenberg
authors: Josef
authors: J
authors: Miersch
authors: Beata
authors: B
authors: Rutz
authors: Frank
authors: F
authors: Strittmatter
authors: Raphaela
authors: R
authors: Waidelich
authors: Christian G
authors: CG
authors: Stief
authors: Christian
authors: C
authors: Gratzke
mesh_terms: D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000378:metabolism; D033966:Adaptor Protein Complex beta Subunits / Q000378:metabolism*; D058646:Adrenergic alpha-1 Receptor Agonists / Q000494:pharmacology; D015153:Blotting, Western; D002243:Carbolines / Q000494:pharmacology; D051242:Caveolin 1 / Q000378:metabolism*; D033941:Clathrin Light Chains / Q000378:metabolism*; D034285:Dynamin II / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D008297:Male; D011467:Prostate / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*
chemical_list: D000089982:ADP-Ribosylation Factor 6; D033966:Adaptor Protein Complex beta Subunits; D058646:Adrenergic alpha-1 Receptor Agonists; D002243:Carbolines; D051242:Caveolin 1; D033941:Clathrin Light Chains; D018340:Receptors, Adrenergic, alpha-1; C009804:tryptoline; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human; D034285:Dynamin II