TY - JOUR
T1 - Mechanism of IFN-γ-induced endocytosis of tight junction proteins
T2 - Myosin II-dependent vacuolarization of the apical plasma membrane
AU - Utech, Markus
AU - Ivanov, Andrei I.
AU - Samarin, Stanislav N.
AU - Bruewer, Matthias
AU - Turner, Jerrold R.
AU - Mrsny, Randall J.
AU - Parkos, Charles A.
AU - Nusrat, Asma
PY - 2005/7/29
Y1 - 2005/7/29
N2 - Disruption of epithelial barrier by proinflammatory cytokines such as IFN-ã represents a major pathophysiological consequence of intestinal inflammation. We have previously shown that IFN-γ increases paracellular permeability in model T84 epithelial cells by inducing endocytosis of tight junction (TJ) proteins occludin, JAM-A, and claudin-1. The present study was designed to dissect mechanisms of IFN-γ-induced endocytosis of epithelial TJ proteins. IFN-γ treatment of T84 cells resulted in internalization of TJ proteins into large actin-coated vacuoles that originated from the apical plasma membrane and resembled the vacuolar apical compartment (VAC) previously observed in epithelial cells that lose cell polarity. The IFN-γ dependent formation of VACs required ATPase activity of a myosin II motor but was not dependent on rapid turnover of F-actin. In addition, activated myosin II was observed to colocalize with VACs after IFN-γ exposure. Pharmacological analyses revealed that formation of VACs and endocytosis of TJ proteins was mediated by Rho-associated kinase (ROCK) but not myosin light chain kinase (MLCK). Furthermore, IFN-γ treatment resulted in activation of Rho GTPase and induced expressional up-regulation of ROCK. These results, for the first time, suggest that IFN-γ induces endocytosis of epithelial TJ proteins via RhoA/ROCK-mediated, myosin II-dependent formation of VACs.
AB - Disruption of epithelial barrier by proinflammatory cytokines such as IFN-ã represents a major pathophysiological consequence of intestinal inflammation. We have previously shown that IFN-γ increases paracellular permeability in model T84 epithelial cells by inducing endocytosis of tight junction (TJ) proteins occludin, JAM-A, and claudin-1. The present study was designed to dissect mechanisms of IFN-γ-induced endocytosis of epithelial TJ proteins. IFN-γ treatment of T84 cells resulted in internalization of TJ proteins into large actin-coated vacuoles that originated from the apical plasma membrane and resembled the vacuolar apical compartment (VAC) previously observed in epithelial cells that lose cell polarity. The IFN-γ dependent formation of VACs required ATPase activity of a myosin II motor but was not dependent on rapid turnover of F-actin. In addition, activated myosin II was observed to colocalize with VACs after IFN-γ exposure. Pharmacological analyses revealed that formation of VACs and endocytosis of TJ proteins was mediated by Rho-associated kinase (ROCK) but not myosin light chain kinase (MLCK). Furthermore, IFN-γ treatment resulted in activation of Rho GTPase and induced expressional up-regulation of ROCK. These results, for the first time, suggest that IFN-γ induces endocytosis of epithelial TJ proteins via RhoA/ROCK-mediated, myosin II-dependent formation of VACs.
UR - http://www.scopus.com/inward/record.url?scp=26244442836&partnerID=8YFLogxK
U2 - 10.1091/mbc.E05-03-0193
DO - 10.1091/mbc.E05-03-0193
M3 - Article
AN - SCOPUS:26244442836
SN - 1059-1524
VL - 16
SP - 5040
EP - 5052
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
IS - 10
ER -