Related Experiment Video
Updated: Jul 20, 2026

Functional Assessment of Intestinal Tight Junction Barrier and Ion Permeability in Native Tissue by Ussing Chamber Technique
Published on: May 26, 2021
Na-K-ATPase regulates tight junction permeability through occludin phosphorylation in pancreatic epithelial cells
Sigrid A Rajasekaran1, Sonali P Barwe, Jegan Gopal
1Department of Pathology and Laboratory Medicine, Rm. 13-344 CHS, University of California, Los Angeles, Los Angeles, CA 90095, USA. arajasekaran@mednet.ucla.edu
Abstract:
Tight junctions are crucial for maintaining the polarity and vectorial transport functions of epithelial cells. We and others have shown that Na-K-ATPase plays a key role in the organization and permeability of tight junctions in mammalian cells and analogous septate junctions in Drosophila. However, the mechanism by which Na-K-ATPase modulates tight junctions is not known. In this study, using a well-differentiated human pancreatic epithelial cell line HPAF-II, we demonstrate that Na-K-ATPase is present at the apical junctions and forms a complex with protein phosphatase-2A, a protein known to be present at tight junctions. Inhibition of Na-K-ATPase ion transport function reduced protein phosphatase-2A activity, hyperphosphorylated occludin, induced rearrangement of tight junction strands, and increased permeability of tight junctions to ionic and nonionic solutes. These data suggest that Na-K-ATPase is required for controlling the tight junction gate function.
Related Concept Videos
Tight Junctions
Tension Response at Adherens Junctions
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin homology) domains...
ATP Driven Pumps III: V-type Pumps
The peripheral or cytosolic V1 domain with eight subunits is involved in ATP hydrolysis. The integral or transmembrane V0 domain containing at least five subunits...
Overview of Cell-Cell Junctions
Occluding or Tight Junctions
Tight...
Adherens Junctions
Adherens Junctions are Dynamic
The endothelial cells...
Cell Motility through Blebbing
Blebbing Through the Matrix
In multicellular...

