Abstract
The apical junctional complex is composed of various cell adhesion molecules and cytoplasmic plaque proteins. Using a monoclonal antibody that recognizes a chicken 155-kDa cytoplasmic antigen (p155) localizing at the apical junctional complex, we have cloned a cDNA of its mouse homologue. The full-length cDNA of mouse p155 encoded a 148-kDa polypeptide containing a coiled-coil domain with sequence similarity to cingulin, a tight junction (TJ)-associated plaque protein. We designated this protein JACOP (junction-associated coiled-coil protein). Immunofluorescence staining showed that JACOP was concentrated in the junctional complex in various types of epithelial and endothelial cells. Furthermore, in the liver and kidney, JACOP was also distributed along non-junctional actin filaments. Upon immunoelectron microscopy, JACOP was found to be localized to the undercoat of TJs in the liver, but in some tissues, its distribution was not restricted to TJs but extended to the area of adherens junctions. Overexpression studies have revealed that JACOP was recruited to the junctional complex in epithelial cells and to cell-cell contacts and stress fibers in fibroblasts. These findings suggest that JACOP is involved in anchoring the apical junctional complex, especially TJs, to actin-based cytoskeletons.
Highlights
Tight junctions (TJs),1 the most apical component of the junctional complex, play crucial roles in the epithelial and endothelial barrier function [1,2,3,4,5]
C-terminal halves of ZO-1 and ZO-2 were shown to bind to F-actin in vitro (19 –21), suggesting that these membraneassociated guanylate kinases establish the molecular link between the TJ membrane and the actin cytoskeleton
We have cloned cDNA encoding JACOP, a novel plaque protein localizing at the apical junctional complex including TJs and AJs
Summary
Cloning of Mouse JACOP cDNA and Mouse Cingulin cDNA—A TJand AJ-enriched plasma membrane fraction was isolated from chick liver as described previously [37]. 5Ј-TACTATGGCTGGAGTGT-3Ј and 5Ј-CTGCAGCTGCTCATTCA-3Ј designed from the sequence information in this mouse EST, a 348-base DNA fragment was amplified by PCR from mouse lung cDNA prepared from mouse lung total RNA with Superscript II reverse transcriptase (Invitrogen). This fragment was used as a template to generate a digoxigenin (DIG)-labeled hybridization probe with the DIG High Prime labeling kit (Roche Applied Science), and hybridization screening was performed using a Lambda ZAP mouse lung cDNA library (Clontech).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
