Tricellulin forms homomeric and heteromeric tight junctional complexes

Area of Science:

• Cell biology
• Epithelial biology
• Protein trafficking

Background:

• Tight junctions seal paracellular clefts, crucial for epithelial and endothelial barrier function.
• Occludin and claudins are key proteins in establishing tight junction barrier function.
• Tricellular contacts, where three cells meet, present a unique barrier challenge.

Purpose of the Study:

• To investigate the role of tricellulin domains in its localization and function at tricellular contacts.
• To elucidate the transport mechanisms and complex formation of tricellulin within tight junctions.
• To extend the existing model of tight junction organization involving tricellulin and occludin.

Main Methods:

• Utilized Madin-Darby canine kidney (MDCK) cells for experimental analysis.
• Investigated the function of tricellulin's N-terminal and C-terminal domains.
• Analyzed homomeric tricellulin-tricellulin and heteromeric tricellulin-occludin complexes.

Main Results:

• The C-terminus of tricellulin is essential for its movement to the basolateral membrane.
• The N-terminal domain of tricellulin directs it to specific tricellular contact sites.
• Identified homomeric and heteromeric complexes involving tricellulin and occludin.

Conclusions:

• Tricellulin's domains play distinct roles in its trafficking and localization.
• Tricellulin and occludin form complexes and are co-transported to junctional edges.
• Separation of tricellulin and occludin occurs during the formation of tricellular contacts.