RNA-binding proteins CUG-binding protein 1 (CUGBP1) and HuR are highly expressed 
in epithelial tissues and modulate the stability and translation of target 
mRNAs. Here we present evidence that CUGBP1 and HuR jointly regulate the 
translation of occludin and play a crucial role in the maintenance of tight 
junction (TJ) integrity in the intestinal epithelial cell monolayer. CUGBP1 and 
HuR competed for association with the same occludin 3'-untranslated region 
element and regulated occludin translation competitively and in opposite 
directions. CUGBP1 overexpression decreased HuR binding to occludin mRNA, 
repressed occludin translation, and compromised the TJ barrier function, whereas 
HuR overexpression inhibited CUGBP1 association with occludin mRNA and promoted 
occludin translation, thereby enhancing the barrier integrity. Repression of 
occludin translation by CUGBP1 was due to the colocalization of CUGBP1 and 
tagged occludin RNA in processing bodies (P-bodies), and this colocalization was 
prevented by HuR overexpression. These findings indicate that CUGBP1 represses 
occludin translation by increasing occludin mRNA recruitment to P-bodies, 
whereas HuR promotes occludin translation by blocking occludin mRNA 
translocation to P-bodies via the displacement of CUGBP1.