title: Tricellulin forms homomeric and heteromeric tight junctional complexes.
abstract: Sealing of the paracellular cleft by tight junctions is of central importance for epithelia and endothelia to function as efficient barriers between the extracellular space and the inner milieu. Occludin and claudins represent the major tight junction components involved in establishing this barrier function. A special situation emerges at sites where three cells join together. Tricellulin, a recently identified tetraspan protein concentrated at tricellular contacts, was reported to organize tricellular as well as bicellular tight junctions. Here we show that in MDCK cells, the tricellulin C-terminus is important for the basolateral translocation of tricellulin, whereas the N-terminal domain appears to be involved in directing tricellulin to tricellular contacts. In this respect, identification of homomeric tricellulin-tricellulin and of heteromeric tricellulin-occludin complexes extends a previously published model and suggests that tricellulin and occludin are transported together to the edges of elongating bicellular junctions and get separated when tricellular contacts are formed.
authors.affiliation: Institute of Biochemistry II, Jena University Hospital, Nonnenplan 2, 07743, Jena, Germany.
authors.forename: Julie K
authors.initials: JK
authors.lastname: Westphal
authors.forename: Max J
authors.initials: MJ
authors.lastname: Dörfel
authors.forename: Susanne M
authors.initials: SM
authors.lastname: Krug
authors.forename: Jimmi D
authors.initials: JD
authors.lastname: Cording
authors.forename: Jörg
authors.initials: J
authors.lastname: Piontek
authors.forename: Ingolf E
authors.initials: IE
authors.lastname: Blasig
authors.forename: Rudolf
authors.initials: R
authors.lastname: Tauber
authors.forename: Michael
authors.initials: M
authors.lastname: Fromm
authors.forename: Otmar
authors.initials: O
authors.lastname: Huber
mesh_terms: D002460:Cell Line; D057167:Claudins / Q000235:genetics / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D005110:Extracellular Space / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D062793:Occludin; D021381:Protein Transport / Q000235:genetics; D059470:Tetraspanins; D019108:Tight Junctions / Q000235:genetics / Q000378:metabolism*
chemical_list: D057167:Claudins; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; C485950:TSPAN32 protein, human; D059470:Tetraspanins