title: Tumor suppressor scribble regulates assembly of tight junctions in the intestinal epithelium.
abstract: Formation of the epithelial barrier and apico-basal cell polarity represent two characteristics and mutually dependent features of differentiated epithelial monolayers. They are controlled by special adhesive structures, tight junctions (TJs), and polarity protein complexes that define the apical and the basolateral plasma membrane. The functional interplay between TJs and polarity complexes remains poorly understood. We investigated the role of Scribble, a basolateral polarity protein and known tumor suppressor, in regulating TJs in human intestinal epithelium. Scribble was enriched at TJs in T84 and SK-CO15 intestinal epithelial cell monolayers and sections of normal human colonic mucosa. siRNA-mediated knockdown of Scribble in SK-CO15 cells attenuated development of epithelial barrier and inhibited TJ reassembly independently of other basolateral polarity proteins Lgl-1 and Dlg-1. Scribble selectively co-imunoprecipitated with TJ protein ZO-1, and ZO-1 was important for Scribble recruitment to intercellular junctions and TJ reassembly. Lastly, Scribble was mislocalized from TJs and its expression down-regulated in interferon-gamma-treated T84 cell monolayers and inflamed human intestinal mucosa in vivo. We conclude that Scribble is an important regulator of TJ functions and plasticity in the intestinal epithelium. Down-regulation of Scribble may mediate mucosal barrier breakdown during intestinal inflammation.
authors: Gastroenterology and Hepatology Division, Department of Medicine, University of Rochester, 601 Elmwood Avenue, Box 646, Rochester, NY 14642, USA. andrei_ivanov@urmc.rochester.edu
authors: Andrei I
authors: AI
authors: Ivanov
authors: Cheryl
authors: C
authors: Young
authors: Kyle
authors: K
authors: Den Beste
authors: Christopher T
authors: CT
authors: Capaldo
authors: Patrick O
authors: PO
authors: Humbert
authors: Patrick
authors: P
authors: Brennwald
authors: Charles A
authors: CA
authors: Parkos
authors: Asma
authors: A
authors: Nusrat
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D000074288:Discs Large Homolog 1 Protein; D015536:Down-Regulation / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000473:pathology; D007371:Interferon-gamma / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C513314:DLG1 protein, human; D000074288:Discs Large Homolog 1 Protein; D008565:Membrane Proteins; D010750:Phosphoproteins; D034741:RNA, Small Interfering; C480591:SCRIB protein, human; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; D025521:Tumor Suppressor Proteins; D062826:Zonula Occludens-1 Protein; D007371:Interferon-gamma