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Article: Dissecting the structural and functional roles of the S3-S4 linker of pacemaker (hyperpolarization-activated cyclic nucleotide-modulated) channels by systematic length alterations

TitleDissecting the structural and functional roles of the S3-S4 linker of pacemaker (hyperpolarization-activated cyclic nucleotide-modulated) channels by systematic length alterations
Authors
KeywordsSpecies Index: Animalia
Insertion Sequences
Issue Date2004
PublisherAmerican Society for Biochemistry and Molecular Biology, Inc. The Journal's web site is located at http://www.jbc.org/
Citation
Journal Of Biological Chemistry, 2004, v. 279 n. 42, p. 43752-43759 How to Cite?
AbstractI f or I h, a key player in neuronal and cardiac pacing, is encoded by the hyperpolarization-activated cyclic nucleotide-modulated (HCN) channel gene family. We have recently reported that the S3-S4 linker (i.e. residues 229EKGMDSEVY 237 of HCN1) prominently influences the activation phenotypes of HCN channels and that part of the linker may conform a secondary helical structure. Here we further dissected the structural and functional roles of this linker by systematic alterations of its length. In contrast to voltage-gated K + channels, complete deletion of the S3-S4 linker (Δ229-237) did not produce functional channels. Similarly, the deletions Δ229-234, Δ232-234, and Δ232-237 also abolished normal current activity. Interestingly, Δ229-231, Δ233-237, Δ234-237, Δ235-237, Δ229-231/Δ233-237, Δ229-231/Δ234-237, and Δ229-231/Δ235-237 all yielded robust hyperpolarization-activated inward currents, indicating that loss-of-function caused by deletion could be rescued by keeping the single functionally important residue Met 232 alone. Whereas shortening the linker by deletion generally shifted steady-state activation in the depolarizing direction (e.g. ΔV 1/2 of Δ229-231, Δ233-237, Δ235-237 >+10 mV relative to wild type), linker prolongation by duplicating the entire linker (Dup229-237) or by glutamine insertion (InsQ233Q, InsQQ233QQ and InsQQQ233QQQ, or Ins237QQQ) produced length-dependent progressive hyperpolarizing activation shifts (-35 mV < ΔV 1/2 < -4 mV). Based on these results, we conclude that only Met 232 is prerequisite for channels to function, but the length and other constituents of the S3-S4 linker shape the ultimate activation phenotype. Our results also highlight several evolutionary similarities and differences between HCN and voltage-gated K + channels. Manipulations of the S3-S4 linker length may provide a flexible approach to customize HCN gating for engineering electrically active cells (such as stem cell-derived neuronal and cardiac pacemakers) for gene- and cell-based therapies.
Persistent Identifierhttp://hdl.handle.net/10722/91439
ISSN
2015 Impact Factor: 4.258
2015 SCImago Journal Rankings: 3.151
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorSuk, YTen_HK
dc.contributor.authorLesso, Hen_HK
dc.contributor.authorLi, RAen_HK
dc.date.accessioned2010-09-17T10:19:25Z-
dc.date.available2010-09-17T10:19:25Z-
dc.date.issued2004en_HK
dc.identifier.citationJournal Of Biological Chemistry, 2004, v. 279 n. 42, p. 43752-43759en_HK
dc.identifier.issn0021-9258en_HK
dc.identifier.urihttp://hdl.handle.net/10722/91439-
dc.description.abstractI f or I h, a key player in neuronal and cardiac pacing, is encoded by the hyperpolarization-activated cyclic nucleotide-modulated (HCN) channel gene family. We have recently reported that the S3-S4 linker (i.e. residues 229EKGMDSEVY 237 of HCN1) prominently influences the activation phenotypes of HCN channels and that part of the linker may conform a secondary helical structure. Here we further dissected the structural and functional roles of this linker by systematic alterations of its length. In contrast to voltage-gated K + channels, complete deletion of the S3-S4 linker (Δ229-237) did not produce functional channels. Similarly, the deletions Δ229-234, Δ232-234, and Δ232-237 also abolished normal current activity. Interestingly, Δ229-231, Δ233-237, Δ234-237, Δ235-237, Δ229-231/Δ233-237, Δ229-231/Δ234-237, and Δ229-231/Δ235-237 all yielded robust hyperpolarization-activated inward currents, indicating that loss-of-function caused by deletion could be rescued by keeping the single functionally important residue Met 232 alone. Whereas shortening the linker by deletion generally shifted steady-state activation in the depolarizing direction (e.g. ΔV 1/2 of Δ229-231, Δ233-237, Δ235-237 >+10 mV relative to wild type), linker prolongation by duplicating the entire linker (Dup229-237) or by glutamine insertion (InsQ233Q, InsQQ233QQ and InsQQQ233QQQ, or Ins237QQQ) produced length-dependent progressive hyperpolarizing activation shifts (-35 mV < ΔV 1/2 < -4 mV). Based on these results, we conclude that only Met 232 is prerequisite for channels to function, but the length and other constituents of the S3-S4 linker shape the ultimate activation phenotype. Our results also highlight several evolutionary similarities and differences between HCN and voltage-gated K + channels. Manipulations of the S3-S4 linker length may provide a flexible approach to customize HCN gating for engineering electrically active cells (such as stem cell-derived neuronal and cardiac pacemakers) for gene- and cell-based therapies.en_HK
dc.languageengen_HK
dc.publisherAmerican Society for Biochemistry and Molecular Biology, Inc. The Journal's web site is located at http://www.jbc.org/en_HK
dc.relation.ispartofJournal of Biological Chemistryen_HK
dc.subjectSpecies Index: Animaliaen_HK
dc.subjectInsertion Sequencesen_HK
dc.subject.meshAmino Acid Sequenceen_HK
dc.subject.meshAnimalsen_HK
dc.subject.meshCyclic Nucleotide-Gated Cation Channelsen_HK
dc.subject.meshIon Channels - genetics - physiologyen_HK
dc.subject.meshKineticsen_HK
dc.subject.meshMembrane Potentials - physiologyen_HK
dc.subject.meshMiceen_HK
dc.subject.meshModels, Molecularen_HK
dc.subject.meshMolecular Sequence Dataen_HK
dc.subject.meshMutagenesis, Site-Directeden_HK
dc.subject.meshNerve Tissue Proteins - genetics - physiologyen_HK
dc.subject.meshPeptide Fragments - chemistry - pharmacologyen_HK
dc.subject.meshPolymerase Chain Reactionen_HK
dc.subject.meshPotassium Channelsen_HK
dc.subject.meshProtein Conformationen_HK
dc.subject.meshRecombinant Fusion Proteins - metabolismen_HK
dc.subject.meshSequence Deletionen_HK
dc.titleDissecting the structural and functional roles of the S3-S4 linker of pacemaker (hyperpolarization-activated cyclic nucleotide-modulated) channels by systematic length alterationsen_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.doi10.1074/jbc.M408747200en_HK
dc.identifier.pmid15299004en_HK
dc.identifier.scopuseid_2-s2.0-6344255128en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-6344255128&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume279en_HK
dc.identifier.issue42en_HK
dc.identifier.spage43752en_HK
dc.identifier.epage43759en_HK
dc.identifier.isiWOS:000224383100050-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridSuk, YT=6603542706en_HK
dc.identifier.scopusauthoridLesso, H=6507506626en_HK
dc.identifier.scopusauthoridLi, RA=7404724466en_HK

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