What are occludin and claudin?
Claudin and occludin are major transmembrane proteins of the tight junction that provide tight control over paracellular diffusion within an epithelium. Interestingly, claudin and occludin are often targeted and misplaced by viruses,1, 6 bacteria,7, 8 and inflammatory cytokines.
What do Claudins do?
Claudins are tetraspan transmembrane proteins of tight junctions. They determine the barrier properties of this type of cell–cell contact existing between the plasma membranes of two neighbouring cells, such as occurring in endothelia or epithelia.
Where are claudin protein found in?
The claudin family consists of 24 known transmembrane proteins exhibiting distinct tissue- and development-specific distribution patterns [37, 38]. They are detected in both epithelial and endothelial cells and form a complex with occludin and/or JAMs [32, 39].
Is Occludin a protein?
Function. Occludin is an important protein in tight junction function. Studies have shown that rather than being important in tight junction assembly, occludin is important in tight junction stability and barrier function.
Where are claudins found?
kidney
Claudins are found in the kidney at locations other than the tubule epithelium. Claudins-5 and -15 are known to be predominantly endothelial claudins and are indeed expressed in the endothelia of renal blood vessels (59). Claudin-1 has been detected in parietal epithelial cells of Bowman’s capsule (59).
What does high zonulin mean?
High levels of zonulin have been associated with increased intestinal permeability, as zonulin induces the breakdown of the tight junctions between intestinal epithelial cells.
What does low zonulin mean?
Given that low zonulin reflects low gut permeability, our findings indicate that Ruminococcaceae have a protective effect on gut barrier integrity.
Where is occludin found in the cell?
Occludin is ubiquitously expressed in epithelial cells, localizing predominantly at bicellular junctions (junctions where two cells meet). Its role is poorly understood.
Why is the C-terminus of occludin important?
The C-terminus of occludin is important in receiving and transmitting cell survival signals. In standard cells, loss or disruption of occludin and other tight junction proteins leads to initiation of apoptosis through extrinsic pathways.
Where is occludin located in the tight junctions?
Occludin. Occludin is a 65-kDa (522-amino acid polypeptide -human) integral plasma-membrane protein located at the tight junctions, described for the first time in 1993 by Shoichiro Tsukita. Together with the Claudin group of proteins, it is the main component of the tight junctions.
How does occludin degradation affect BBB endothelial cells?
These data indicate that occludin degradation inflicted during ischemia makes BBB endothelial cells more vulnerable to reperfusion-associated stress stimuli. Keywords: blood-brain barrier; cerebral hemorrhage following thrombolysis; endothelial cell death; ischemic Stroke; occludin.
