title: Protein-binding domains of the tight junction protein, ZO-2, are highly conserved between avian and mammalian species.
abstract: The tight junction is composed of many proteins and includes three members of the MAGUK (membrane-associated, guanylate kinase-like) protein family: ZO-1, ZO-2, and ZO-3. ZO-2 was cloned and sequenced from embryonic chicken retina. Antibodies against a short ZO-2 peptide immunolabeled the outer limiting membrane (an adherens junction of the neural retina) and the apical junctional complexes of the retinal pigment epithelium. Each ZO family member contains a homologous series of protein-binding domains: three distinct PDZ domains and src homology 3 (SH3), guanylate kinase-like (GuK), and acidic domains. Compared with human and canine ZO-2s, the PDZ and SH3 domains are the most conserved (90-95% amino acid sequence identity). These domains are only 50-71% identical with the homologous domains of ZO-1 and ZO-3. Although the sequence is less conserved for regions that link the protein-binding domains, the length of those regions is conserved in ZO-2s. The postacidic (C-terminal) region is the least conserved. The evolutionary pressure to maintain the sequence of the protein-binding domains suggests that homologous domains have different functions in ZO-1, ZO-2, and ZO-3.
authors.affiliation: Department of Surgery and Department of Ophthalmology and Visual Sciences, Yale University School of Medicine, New Haven, Connecticut, 06520-8062, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Collins
authors.forename: L J
authors.initials: LJ
authors.lastname: Rizzolo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry; D002642:Chick Embryo; D017124:Conserved Sequence; D004285:Dogs; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D062825:Zonula Occludens Proteins; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D010750:Phosphoproteins; C569042:TJP1 protein, human; C569046:TJP2 protein, human; C111873:TJP3 protein, human; D062825:Zonula Occludens Proteins; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein