Self-association of PAR-3-mediated by the conserved N-terminal domain contributes to the development of epithelial tight junctions
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Updated: Sep 26, 2026

Immunostaining and Dye Penetration Experiments to Define Core Pleated Septate Junction Proteins in Drosophila Embryonic Epithelia
Published on: February 27, 2026
Keiko Mizuno1, Atsushi Suzuki, Tomonori Hirose
1Department of Molecular Biology, Yokohama City University School of Medicine, Fuku-ura 3-9, Kanazawa-ku, Yokohama 236-0004, Japan.
Abstract:
PAR-3 is a scaffold-like PDZ-containing protein that forms a complex with PAR-6 and atypical protein kinase C (PAR-3-atypical protein kinase C-PAR-6 complex) and contributes to the establishment of cell polarity in a wide variety of biological contexts. In mammalian epithelial cells, it localizes to tight junctions, the most apical end of epithelial cell-cell junctions, and contributes to the formation of functional tight junctions. However, the mechanism by which PAR-3 localizes to tight junctions and contributes to their formation remains to be clarified. Here we show that the N-terminal conserved region, CR1-(1-86), and the sequence 937-1,024 are required for its recruitment to the most apical side of the cell-cell contact region in epithelial Madin-Darby canine kidney cells. We also show that CR1 self-associates to form an oligomeric complex in vivo and in vitro. Further, overexpression of CR1 in Madin-Darby canine kidney cells disturbs the distribution of atypical protein kinase C and PAR-6 as well as PAR-3 and delays the formation of functional tight junctions. These results support the notion that the CR1-mediated self-association of the PAR-3-containing protein complex plays a role during the formation of functional tight junctions.
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