Cingulin contains globular and coiled-coil domains and interacts with ZO-1, ZO-2, ZO-3, and myosin.
J Cell Biol
; 147(7): 1569-82, 1999 Dec 27.
Article
in En
| MEDLINE
| ID: mdl-10613913
ABSTRACT
We characterized the sequence and protein interactions of cingulin, an M(r) 140-160-kD phosphoprotein localized on the cytoplasmic surface of epithelial tight junctions (TJ). The derived amino acid sequence of a full-length Xenopus laevis cingulin cDNA shows globular head (residues 1-439) and tail (1,326-1,368) domains and a central alpha-helical rod domain (440-1,325). Sequence analysis, electron microscopy, and pull-down assays indicate that the cingulin rod is responsible for the formation of coiled-coil parallel dimers, which can further aggregate through intermolecular interactions. Pull-down assays from epithelial, insect cell, and reticulocyte lysates show that an NH(2)-terminal fragment of cingulin (1-378) interacts in vitro with ZO-1 (K(d) approximately 5 nM), ZO-2, ZO-3, myosin, and AF-6, but not with symplekin, and a COOH-terminal fragment (377-1,368) interacts with myosin and ZO-3. ZO-1 and ZO-2 immunoprecipitates contain cingulin, suggesting in vivo interactions. Full-length cingulin, but not NH(2)-terminal and COOH-terminal fragments, colocalizes with endogenous cingulin in transfected MDCK cells, indicating that sequences within both head and rod domains are required for TJ localization. We propose that cingulin is a functionally important component of TJ, linking the submembrane plaque domain of TJ to the actomyosin cytoskeleton.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Phosphoproteins
/
Carrier Proteins
/
Myosins
/
Xenopus Proteins
/
Membrane Proteins
Limits:
Animals
Language:
En
Journal:
J Cell Biol
Year:
1999
Type:
Article
Affiliation country:
Italy