DIRECT ASSOCIATION OF THE GAP JUNCTION PROTEIN CONNEXIN-43 WITH ZO-1 IN CARDIAC MYOCYTES

Citation
T. Toyofuku et al., DIRECT ASSOCIATION OF THE GAP JUNCTION PROTEIN CONNEXIN-43 WITH ZO-1 IN CARDIAC MYOCYTES, The Journal of biological chemistry, 273(21), 1998, pp. 12725-12731
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biology
ISSN journal
0021-9258
Volume
273
Issue
21
Year of publication
1998
Pages
12725 - 12731
Database
ISI
SICI code
0021-9258(1998)273:21<12725:DAOTGJ>2.0.ZU;2-Y
Abstract
The gap junction protein connexin-43 is normally located at the interc alated discs of cardiac myocytes, and it plays a critical role in the synchronization of their contraction. The mechanism by which connexin- 43 is localized within cardiac myocytes is unknown. However, localizat ion of connexin 43 likely involves an interaction with the cytoskeleto n; immunofluorescence microscopy showed that in cardiac myocytes, conn exin-43 specifically colocalizes with the cytoskeletal proteins ZO-1 a nd cu-spectrin. In transfected HEK293 cells, immunoprecipitation exper iments using coexpressed epitope-tagged connexin-43 and ZO-1 indicated that ZO-1 links connexin-43 with alpha-spectrin, The domains responsi ble for the protein-protein interaction between connexin-43 and ZO-1 w ere identified using affinity binding assays with deleted ZO-1 and con nexin-43 fusion proteins, Immunoblot analysis of associated proteins s howed that the C-terminal domain of connexin-43 binds to the N-termina l domain of ZO-1, The role of this linkage in gap junction formation w as examined by a dominant-negative assay using the N-terminal domain o f ZO-1, Overexpression of the N-terminal domain of ZO-1 in connexin-43 -expressing cells resulted in redistribution of connexin-43 from cell- cell interfaces to cytoplasmic structures; this intracellular redistri bution of connexin-43 coincided with a loss of electrical coupling. We therefore conclude that the linkage between connexin-43 and alpha-spe ctrin, via ZO-1, may serve to localize connexin-43 at the intercalated discs, thereby generating functional gap junctions in cardiac myocyte s.