Tumor suppressor scribble regulates assembly of tight junctions in the intestinal epithelium.
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.
Ivanov
Andrei I
AI
Gastroenterology and Hepatology Division, Department of Medicine, University of Rochester, 601 Elmwood Avenue, Box 646, Rochester, NY 14642, USA. andrei_ivanov@urmc.rochester.edu
Young
Cheryl
C
Den Beste
Kyle
K
Capaldo
Christopher T
CT
Humbert
Patrick O
PO
Brennwald
Patrick
P
Parkos
Charles A
CA
Nusrat
Asma
A
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
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