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Article: Expression of chimeric connexins reveals new properties of the formation and gating behavior of gap junction channels

TitleExpression of chimeric connexins reveals new properties of the formation and gating behavior of gap junction channels
Authors
KeywordsConnexin32
Connexin43
Gap junction
Intercellular communication
Voltage xenopus oocyte
Issue Date1994
PublisherThe Company of Biologists Ltd
Citation
Journal Of Cell Science, 1994, v. 107 n. 4, p. 955-967 How to Cite?
AbstractDirect intercellular communication occurs through specialized channels, which are formed by the interaction of two half-channels, or connexons, contributed by each of the two participating cells. The ability to establish intercellular communication is specified, in part, by the expression of different structural proteins, termed connexins. Connexins can control the establishment of intercellular communication by selectively pairing with some but not other family members. To characterize the protein domains that allow connexins to recognize and discriminate between alternative partners, we have created chimeras composed of selected regions of rat connexin43, which forms channels with Xenopus connexin38, and rat connexin32, which cannot. Pairs of Xenopus oocytes were used to test the ability of the chimeras to form homotypic channels with themselves, and heterotypic channels with the parent connexins or with endogenous Xenopus connexin38. While all hybrid molecules tested were efficiently expressed by oocytes, most were devoid of functional activity. A chimera consisting of connexin32 from the N terminus to the second transmembrane domain, fused to connexin43 from the middle cytoplasmic loop to the C terminus, designated as 3243H4, was able to pair functionally with Xenopus connexin38 and one of its parent connexins, connexin43. Voltage-dependent closure of heterotypic channels containing 3243H4 was asymmetric, exhibited novel characteristics that were not predicted by the behavior of the parent connexins and was dependent on the type of connexin with which 3243H4 was paired. In contrast, 3243H4 was unable to form functional channels with either itself or the other parent, connexin32. Together, these results suggest that these connexins are not composed of functionally exchangeable regions and that multiple domains, namely the middle cytoplasmic portion and the second extracellular domain, can influence the interactions between connexins present in adjacent cells. Furthermore, they indicate that voltage gating is not strictly intrinsic behavior for a given connexin, but can be modulated by the partner connexins to which they are paired. Finally, the finding that 3243H4 is functional only in heterotypic configurations, and cannot form homotypic channels, suggests the existence of a novel form of selectivity: self-discrimination. The latter property may represent another mechanism that operates to control the extent of communication between cells.
Persistent Identifierhttp://hdl.handle.net/10722/132764
ISSN
2015 Impact Factor: 4.706
2015 SCImago Journal Rankings: 3.501
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorBruzzone, Ren_HK
dc.contributor.authorWhite, TWen_HK
dc.contributor.authorPaul, DLen_HK
dc.date.accessioned2011-03-28T09:28:49Z-
dc.date.available2011-03-28T09:28:49Z-
dc.date.issued1994en_HK
dc.identifier.citationJournal Of Cell Science, 1994, v. 107 n. 4, p. 955-967en_HK
dc.identifier.issn0021-9533en_HK
dc.identifier.urihttp://hdl.handle.net/10722/132764-
dc.description.abstractDirect intercellular communication occurs through specialized channels, which are formed by the interaction of two half-channels, or connexons, contributed by each of the two participating cells. The ability to establish intercellular communication is specified, in part, by the expression of different structural proteins, termed connexins. Connexins can control the establishment of intercellular communication by selectively pairing with some but not other family members. To characterize the protein domains that allow connexins to recognize and discriminate between alternative partners, we have created chimeras composed of selected regions of rat connexin43, which forms channels with Xenopus connexin38, and rat connexin32, which cannot. Pairs of Xenopus oocytes were used to test the ability of the chimeras to form homotypic channels with themselves, and heterotypic channels with the parent connexins or with endogenous Xenopus connexin38. While all hybrid molecules tested were efficiently expressed by oocytes, most were devoid of functional activity. A chimera consisting of connexin32 from the N terminus to the second transmembrane domain, fused to connexin43 from the middle cytoplasmic loop to the C terminus, designated as 3243H4, was able to pair functionally with Xenopus connexin38 and one of its parent connexins, connexin43. Voltage-dependent closure of heterotypic channels containing 3243H4 was asymmetric, exhibited novel characteristics that were not predicted by the behavior of the parent connexins and was dependent on the type of connexin with which 3243H4 was paired. In contrast, 3243H4 was unable to form functional channels with either itself or the other parent, connexin32. Together, these results suggest that these connexins are not composed of functionally exchangeable regions and that multiple domains, namely the middle cytoplasmic portion and the second extracellular domain, can influence the interactions between connexins present in adjacent cells. Furthermore, they indicate that voltage gating is not strictly intrinsic behavior for a given connexin, but can be modulated by the partner connexins to which they are paired. Finally, the finding that 3243H4 is functional only in heterotypic configurations, and cannot form homotypic channels, suggests the existence of a novel form of selectivity: self-discrimination. The latter property may represent another mechanism that operates to control the extent of communication between cells.en_HK
dc.languageengen_US
dc.publisherThe Company of Biologists Ltden_US
dc.relation.ispartofJournal of Cell Scienceen_HK
dc.subjectConnexin32en_HK
dc.subjectConnexin43en_HK
dc.subjectGap junctionen_HK
dc.subjectIntercellular communicationen_HK
dc.subjectVoltage xenopus oocyteen_HK
dc.titleExpression of chimeric connexins reveals new properties of the formation and gating behavior of gap junction channelsen_HK
dc.typeArticleen_HK
dc.identifier.emailBruzzone, R: bruzzone@hkucc.hku.hken_HK
dc.identifier.authorityBruzzone, R=rp01442en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.pmid8056849-
dc.identifier.scopuseid_2-s2.0-0028230758en_HK
dc.identifier.volume107en_HK
dc.identifier.issue4en_HK
dc.identifier.spage955en_HK
dc.identifier.epage967en_HK
dc.identifier.isiWOS:A1994NG88000020-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridBruzzone, R=7006793327en_HK
dc.identifier.scopusauthoridWhite, TW=35499703300en_HK
dc.identifier.scopusauthoridPaul, DL=7401667165en_HK

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