Dimerization of the scaffolding protein ZO-1 through the second PDZ domain

Dimerization of the scaffolding protein ZO-1 through the second PDZ domain
Engineering Village 2
2006 Elsevier Inc.
Accession number: 063510089895

Title: Dimerization of the scaffolding protein ZO-1 through the second PDZ domain

Authors: Utepbergenov, Darkhan I.; Fanning, Alan S.; Anderson, James M.

Author affiliation: Dept. of Cell and Molecular Physiology, Medical and Biomolecular Research Bldg., University of North Carolina, Chapel Hill, NC 27599-7545, United States

Serial title: Journal of Biological Chemistry

Abbreviated serial title: J. Biol. Chem.

Volume: v 281

Issue: n 34

Issue date: Aug 25 2006

Publication year: 2006

Pages: p 24671-24677

Language: English

ISSN: 0021-9258


Document type: Journal article (JA)

Publisher: American Society for Biochemistry and Molecular Biology Inc., Bethesda, MD 20814, United States

Abstract: The tight junction protein ZO-1 is known to link the transmembrane proteins occludin, claudins, and JAMs to many cytoplasmic proteins and the actin cytoskeleton. Although specific roles for ZO-1 at the tight junction are unknown, it is widely assumed that ZO-1, together with its homologs ZO-2 and ZO-3, serves as a platform to scaffold various transmembrane and cytoplasmic tight junction proteins. Thus the manner in which the zonula occludens (ZO) proteins multimerize has implications for the protein networks they can coordinate. The purpose of our study was to determine whether ZO-1 forms homodimers and to determine the protein interaction region. Using laser light scattering and analytical centrifugation, we show that protein sequences corresponding to the NH2-terminal half of ZO-1 form stable homodimers with a submicromolar equilibrium dissociation constant. Analysis of the molecular weight of different truncated forms of ZO-1 revealed that the second PDZ domain is both necessary and sufficient for dimerization. This interaction does not use the ?-finger motif described for other PDZ dimers. Furthermore, ZO-1 does not dimerize via an Src homology 3 to Guk domain interaction as was demonstrated previously for MAGUKs, like PSD-95. Results from immunoprecipitation experiments with polarized Madin-Darby canine kidney epithelial cells stably transfected with full-length GFP-ZO-1 indicate that a substantial portion of ZO-1 forms homodimers in vivo. As described previously, ZO-1 also forms heterodimers with ZO-2 and ZO-3. We conclude that the dimerization of ZO proteins is unlike that of other MAGUKs and that the previously unrecognized ZO-1 homodimers may allow formation of protein networks distinct from those of heterodimers with ZO-2 and ZO-3. ? 2006 by The American Society for Biochemistry and Molecular Biology, Inc.

Number of references: 23

Ei main heading: Proteins

Ei controlled terms: Molecular weight - Dimers - Immunology - Precipitation (chemical)

Uncontrolled terms: Scaffolding proteins - Actin cytoskeleton - Transmembranes - Protein sequences

Ei classification codes: 804.1 Organic Compounds - 931.3 Atomic & Molecular Physics - 815.1.1 Organic Polymers - 461.9.1 Immunology - 802.3 Chemical Operations

Treatment: Experimental (EXP)

DOI: 10.1074/jbc.M512820200

Database: Compendex

Compilation and indexing terms, ? 2006 Elsevier Inc. All rights reserved
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