Tricellulin (TRIC)

MARVELD2, or tricellulin (TRIC), is an integral membrane protein concentrated at the vertically oriented TJ strands of tricellular contacts.The 555-amino acid protein contains cytoplasmic N and C termini, 2 transmembrane domains, and 2 extracellular loops. Northern blot analysis detected high expression of Tric in epithelium-derived tissues, including small intestine, kidney, and lung. Western blot analysis of mouse epithelial cell lines revealed an approximately 66-kD protein, as well as larger phosphorylated intracellular forms. Immunofluorescence microscopy showed expression of Tric predominantly at tricellular contacts where occludin (OCLN)-positive bicellular TJs converged. Tric-positive structures appeared as short rods through confocal microscopy.