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Article: Modulation of perch connexin35 hemi-channels by cyclic AMP requires a protein kinase a phosphorylation site

TitleModulation of perch connexin35 hemi-channels by cyclic AMP requires a protein kinase a phosphorylation site
Authors
KeywordsElectrical synapse
Gap junction
Neuron
Oocyte
Retina
Issue Date2003
PublisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/34828
Citation
Journal Of Neuroscience Research, 2003, v. 72 n. 2, p. 147-157 How to Cite?
AbstractRetinal neurons are coupled via gap junctions, which function as electrical synapses that are gated by ambient light conditions. Gap junctions connecting either horizontal cells or All amacrine cells are inhibited by the neurotransmitter dopamine, via the activation of the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway. Fish connexin35 (Cx35) and its mouse ortholog, Cx36, are good candidates to undergo dopaminergic modulation, because they have been detected in the inner plexiform layer of the retina, where Type II amacrine cells establish synaptic contacts. We have taken advantage of the ability of certain connexins to form functional connexons (hemi-channels), when expressed in Xenopus oocytes, to investigate whether pharmacological elevation of cAMP modulates voltage-activated hemi-channel currents in single oocytes. Injection of perch Cx35 RNA into Xenopus oocytes induced outward voltage-dependent currents that were recorded at positive membrane potentials. Incubation of oocytes with 8-bromoadenosine 3′,5′-cyclic monophosphate (8-Br-cAMP), a membrane permeable cAMP analog, resulted in a dose-dependent and reversible inhibition of hemi-channel currents at the more positive voltage steps. In contrast, treatment with 8-Br-cAMP did not have any effect on hemi-channel currents induced by skate Cx35. Amino acid sequence comparison of the two fish connexins revealed, in the middle cytoplasmic loop of perch Cx35, the presence of a PKA consensus sequence that was absent in the skate connexin. The results obtained with two constructs in which the putative PKA phosphorylation site was either suppressed (perch Cx35R108Q) or introduced (skate Cx35Q108R) indicate that it is responsible for the inhibition of hemi-channel currents. These studies demonstrate that perch Cx35 is a target of the cAMP/PKA signaling pathway and identify a consensus PKA phosphorylation site that is required for channel gating. © 2003 Wiley-Liss, Inc.
Persistent Identifierhttp://hdl.handle.net/10722/132706
ISSN
2015 Impact Factor: 2.689
2015 SCImago Journal Rankings: 1.261
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorMitropoulou, Gen_HK
dc.contributor.authorBruzzone, Ren_HK
dc.date.accessioned2011-03-28T09:28:25Z-
dc.date.available2011-03-28T09:28:25Z-
dc.date.issued2003en_HK
dc.identifier.citationJournal Of Neuroscience Research, 2003, v. 72 n. 2, p. 147-157en_HK
dc.identifier.issn0360-4012en_HK
dc.identifier.urihttp://hdl.handle.net/10722/132706-
dc.description.abstractRetinal neurons are coupled via gap junctions, which function as electrical synapses that are gated by ambient light conditions. Gap junctions connecting either horizontal cells or All amacrine cells are inhibited by the neurotransmitter dopamine, via the activation of the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway. Fish connexin35 (Cx35) and its mouse ortholog, Cx36, are good candidates to undergo dopaminergic modulation, because they have been detected in the inner plexiform layer of the retina, where Type II amacrine cells establish synaptic contacts. We have taken advantage of the ability of certain connexins to form functional connexons (hemi-channels), when expressed in Xenopus oocytes, to investigate whether pharmacological elevation of cAMP modulates voltage-activated hemi-channel currents in single oocytes. Injection of perch Cx35 RNA into Xenopus oocytes induced outward voltage-dependent currents that were recorded at positive membrane potentials. Incubation of oocytes with 8-bromoadenosine 3′,5′-cyclic monophosphate (8-Br-cAMP), a membrane permeable cAMP analog, resulted in a dose-dependent and reversible inhibition of hemi-channel currents at the more positive voltage steps. In contrast, treatment with 8-Br-cAMP did not have any effect on hemi-channel currents induced by skate Cx35. Amino acid sequence comparison of the two fish connexins revealed, in the middle cytoplasmic loop of perch Cx35, the presence of a PKA consensus sequence that was absent in the skate connexin. The results obtained with two constructs in which the putative PKA phosphorylation site was either suppressed (perch Cx35R108Q) or introduced (skate Cx35Q108R) indicate that it is responsible for the inhibition of hemi-channel currents. These studies demonstrate that perch Cx35 is a target of the cAMP/PKA signaling pathway and identify a consensus PKA phosphorylation site that is required for channel gating. © 2003 Wiley-Liss, Inc.en_HK
dc.languageengen_US
dc.publisherJohn Wiley & Sons, Inc. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/34828en_HK
dc.relation.ispartofJournal of Neuroscience Researchen_HK
dc.subjectElectrical synapseen_HK
dc.subjectGap junctionen_HK
dc.subjectNeuronen_HK
dc.subjectOocyteen_HK
dc.subjectRetinaen_HK
dc.titleModulation of perch connexin35 hemi-channels by cyclic AMP requires a protein kinase a phosphorylation siteen_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.doi10.1002/jnr.10572en_HK
dc.identifier.pmid12671989-
dc.identifier.scopuseid_2-s2.0-0037445916en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0037445916&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume72en_HK
dc.identifier.issue2en_HK
dc.identifier.spage147en_HK
dc.identifier.epage157en_HK
dc.identifier.isiWOS:000182113000002-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridMitropoulou, G=8772857700en_HK
dc.identifier.scopusauthoridBruzzone, R=7006793327en_HK

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