Gap junction protein connexin-43 interacts directly with microtubules.
Curr Biol
; 11(17): 1364-8, 2001 Sep 04.
Article
em En
| MEDLINE
| ID: mdl-11553331
ABSTRACT
Gap junctions are specialized cell-cell junctions that mediate intercellular communication. They are composed of connexin proteins, which form transmembrane channels for small molecules [1, 2]. The C-terminal tail of connexin-43 (Cx43), the most widely expressed connexin member, has been implicated in the regulation of Cx43 channel gating by growth factors [3-5]. The Cx43 tail contains various protein interaction sites, but little is known about binding partners. To identify Cx43-interacting proteins, we performed pull-down experiments using the C-terminal tail of Cx43 fused to glutathione-S-transferase. We find that the Cx43 tail binds directly to tubulin and, like full-length Cx43, sediments with microtubules. Tubulin binding to Cx43 is specific in that it is not observed with three other connexins. We established that a 35-amino acid juxtamembrane region in the Cx43 tail, which contains a presumptive tubulin binding motif, is necessary and sufficient for microtubule binding. Immunofluorescence and immunoelectron microscopy studies reveal that microtubules extend to Cx43-based gap junctions in contacted cells. However, intact microtubules are dispensable for the regulation of Cx43 gap-junctional communication. Our findings suggest that, in addition to its well-established role as a channel-forming protein, Cx43 can anchor microtubule distal ends to gap junctions and thereby might influence the properties of microtubules in contacted cells.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Conexina 43
/
Microtúbulos
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Curr Biol
Assunto da revista:
BIOLOGIA
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Holanda