title: JEAP, a novel component of tight junctions in exocrine cells.
abstract: Tight junctions (TJs) consist of transmembrane proteins and many peripheral membrane proteins. To further characterize the molecular organization of TJs, we attempted here to screen for novel TJ proteins by the fluorescence localization-based expression cloning method. We identified a novel peripheral membrane protein at TJs and named it junction-enriched and -associated protein (JEAP). JEAP consists of 882 amino acids with a calculated molecular weight of 98,444. JEAP contained a polyglutamic acid repeat at the N-terminal region, a coiled-coil domain at the middle region, and a consensus motif for binding to PDZ domains at the C-terminal region. Exogenously expressed JEAP co-localized with ZO-1 and occludin at TJs in polarized Madin-Darby canine kidney cells, but not with claudin-1, JAM, or ZO-1 in L cells. Endogenous JEAP localized at TJs of exocrine cells including pancreas, submandibular gland, lacrimal gland, parotid gland, and sublingual gland, but not at TJs of epithelial cells of small intestine or endothelial cells of blood vessels. The present results indicate that JEAP is a novel component of TJs, which is specifically expressed in exocrine cells.
authors.affiliation: KAN Research Institute Inc., 1 Chudoji-Awata-cho, Shimogyo-ku, Kyoto 600-8815, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Nishimura
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kakizaki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ono
authors.forename: Koji
authors.initials: K
authors.lastname: Morimoto
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Inoue
authors.forename: Toshio
authors.initials: T
authors.lastname: Imai
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Takai
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D018076:DNA, Complementary / Q000378:metabolism; D004285:Dogs; D004727:Endothelium / Q000166:cytology; D005088:Exocrine Glands / Q000166:cytology*; D015723:Gene Library; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D062793:Occludin; D010750:Phosphoproteins / Q000378:metabolism; D011099:Polyglutamic Acid / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D019108:Tight Junctions / Q000737:chemistry*; D014162:Transfection; D062826:Zonula Occludens-1 Protein
chemical_list: D018076:DNA, Complementary; D008565:Membrane Proteins; D062793:Occludin; C568987:Ocln protein, rat; D010750:Phosphoproteins; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D011099:Polyglutamic Acid; D002118:Calcium