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Article: Dominant-negative suppression of HCN1- and HCN2-encoded pacemaker currents by an engineered HCN1 construct: Insights into structure-function relationships and multimerization

TitleDominant-negative suppression of HCN1- and HCN2-encoded pacemaker currents by an engineered HCN1 construct: Insights into structure-function relationships and multimerization
Authors
KeywordsChemicals And Cas Registry Numbers
Issue Date2002
PublisherLippincott Williams & Wilkins. The Journal's web site is located at http://circres.ahajournals.org
Citation
Circulation Research, 2002, v. 90 n. 12, p. 1267-1273 How to Cite?
AbstractIf, a diastolic depolarizing current activated by hyperpolarization, is a key player in cardiac pacing. Despite the fact that If has been known for over 20 years, the encoding genes, namely HCN1 to 4, have only recently been identified. Functional data imply that different HCN isoforms may coassemble to form heteromeric channel complexes, but little direct evidence is available. Subunit stoichiometry is also unknown. Although the pore region of HCN channels contains the glycine-tyrosine-glycine (GYG) signature motif found in K+-selective channels, they permeate both Na+ and K+. In the present study, we probed the functional importance of the GYG selectivity motif in pacemaker channels by replacing this triplet in HCN1 with alanines (GYG349-351AAA or HCN1-AAA). HCN1-AAA did not yield functional currents; coexpression of HCN1-AAA with wild-type (WT) HCN1 suppressed normal channel activity in a dominant-negative manner (55.2±3.2%, 68.3±4.3%, 78.7±1.6%, 91.7±0.8%, and 97.9±0.2% current reduction at -140 mV for WT:AAA cRNA ratios of 4:1, 3:1, 2:1, 1:1, and 1:2, respectively) without affecting gating (steady-state activation, activation and deactivation kinetics) or permeation (reversal potential) properties. HCN1-AAA coexpression, however, did not alter the expressed current amplitudes of Kv1.4 and Kv2.1 channels, indicating that its suppressive effect was channel-specific. Statistical analysis reveals that a single HCN channel is composed of 4 monomeric subunits. Interestingly, HCN1-AAA also inhibited HCN2 in a dominant-negative manner with the same efficacy. We conclude that the GYG motif is a critical determinant of ion permeation for HCN channels, and that HCN1 and HCN2 readily coassemble to form heterotetrameric complexes.
Persistent Identifierhttp://hdl.handle.net/10722/91498
ISSN
2015 Impact Factor: 11.551
2015 SCImago Journal Rankings: 5.755
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorXue, Ten_HK
dc.contributor.authorMarbán, Een_HK
dc.contributor.authorLi, RAen_HK
dc.date.accessioned2010-09-17T10:20:22Z-
dc.date.available2010-09-17T10:20:22Z-
dc.date.issued2002en_HK
dc.identifier.citationCirculation Research, 2002, v. 90 n. 12, p. 1267-1273en_HK
dc.identifier.issn0009-7330en_HK
dc.identifier.urihttp://hdl.handle.net/10722/91498-
dc.description.abstractIf, a diastolic depolarizing current activated by hyperpolarization, is a key player in cardiac pacing. Despite the fact that If has been known for over 20 years, the encoding genes, namely HCN1 to 4, have only recently been identified. Functional data imply that different HCN isoforms may coassemble to form heteromeric channel complexes, but little direct evidence is available. Subunit stoichiometry is also unknown. Although the pore region of HCN channels contains the glycine-tyrosine-glycine (GYG) signature motif found in K+-selective channels, they permeate both Na+ and K+. In the present study, we probed the functional importance of the GYG selectivity motif in pacemaker channels by replacing this triplet in HCN1 with alanines (GYG349-351AAA or HCN1-AAA). HCN1-AAA did not yield functional currents; coexpression of HCN1-AAA with wild-type (WT) HCN1 suppressed normal channel activity in a dominant-negative manner (55.2±3.2%, 68.3±4.3%, 78.7±1.6%, 91.7±0.8%, and 97.9±0.2% current reduction at -140 mV for WT:AAA cRNA ratios of 4:1, 3:1, 2:1, 1:1, and 1:2, respectively) without affecting gating (steady-state activation, activation and deactivation kinetics) or permeation (reversal potential) properties. HCN1-AAA coexpression, however, did not alter the expressed current amplitudes of Kv1.4 and Kv2.1 channels, indicating that its suppressive effect was channel-specific. Statistical analysis reveals that a single HCN channel is composed of 4 monomeric subunits. Interestingly, HCN1-AAA also inhibited HCN2 in a dominant-negative manner with the same efficacy. We conclude that the GYG motif is a critical determinant of ion permeation for HCN channels, and that HCN1 and HCN2 readily coassemble to form heterotetrameric complexes.en_HK
dc.languageengen_HK
dc.publisherLippincott Williams & Wilkins. The Journal's web site is located at http://circres.ahajournals.orgen_HK
dc.relation.ispartofCirculation Researchen_HK
dc.subjectChemicals And Cas Registry Numbersen_HK
dc.subject.meshAmino Acid Motifsen_HK
dc.subject.meshAmino Acid Sequenceen_HK
dc.subject.meshAnimalsen_HK
dc.subject.meshBiological Clocksen_HK
dc.subject.meshCells, Cultureden_HK
dc.subject.meshCyclic Nucleotide-Gated Cation Channelsen_HK
dc.subject.meshElectric Conductivityen_HK
dc.subject.meshIon Channel Gatingen_HK
dc.subject.meshIon Channels - antagonists & inhibitors - chemistry - genetics - physiologyen_HK
dc.subject.meshIon Transporten_HK
dc.subject.meshMacromolecular Substancesen_HK
dc.subject.meshMolecular Sequence Dataen_HK
dc.subject.meshMuscle Proteinsen_HK
dc.subject.meshMutagenesis, Site-Directeden_HK
dc.subject.meshMutationen_HK
dc.subject.meshOocytes - metabolismen_HK
dc.subject.meshPotassium Channelsen_HK
dc.subject.meshSequence Alignmenten_HK
dc.subject.meshStructure-Activity Relationshipen_HK
dc.subject.meshXenopusen_HK
dc.titleDominant-negative suppression of HCN1- and HCN2-encoded pacemaker currents by an engineered HCN1 construct: Insights into structure-function relationships and multimerizationen_HK
dc.typeArticleen_HK
dc.identifier.emailLi, RA:ronaldli@hkucc.hku.hken_HK
dc.identifier.authorityLi, RA=rp01352en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1161/01.RES.0000024390.97889.C6en_HK
dc.identifier.pmid12089064-
dc.identifier.scopuseid_2-s2.0-0037188937en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0037188937&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume90en_HK
dc.identifier.issue12en_HK
dc.identifier.spage1267en_HK
dc.identifier.epage1273en_HK
dc.identifier.isiWOS:000176686200007-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridXue, T=7005064190en_HK
dc.identifier.scopusauthoridMarbán, E=8075977300en_HK
dc.identifier.scopusauthoridLi, RA=7404724466en_HK

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