Linked Life Data

15299004

Source:http://linkedlifedata.com/resource/pubmed/id/15299004

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2004-10-11
pubmed:abstractText
If or Ih, 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 229EKGMDSEVY237 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 (Delta229-237) did not produce functional channels. Similarly, the deletions Delta229-234, Delta232-234, and Delta232-237 also abolished normal current activity. Interestingly, Delta229-231, Delta233-237, Delta234-237, Delta235-237, Delta229-231/Delta233-237, Delta229-231/Delta234-237, and Delta229-231/Delta235-237 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 Met232 alone. Whereas shortening the linker by deletion generally shifted steady-state activation in the depolarizing direction (e.g. DeltaV1/2 of Delta229-231, Delta233-237, Delta235-237 > +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 < DeltaV1/2 < -4 mV). Based on these results, we conclude that only Met232 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.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
43752-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:15299004-Amino Acid Sequence, pubmed-meshheading:15299004-Animals, pubmed-meshheading:15299004-Cyclic Nucleotide-Gated Cation Channels, pubmed-meshheading:15299004-Ion Channels, pubmed-meshheading:15299004-Kinetics, pubmed-meshheading:15299004-Membrane Potentials, pubmed-meshheading:15299004-Mice, pubmed-meshheading:15299004-Models, Molecular, pubmed-meshheading:15299004-Molecular Sequence Data, pubmed-meshheading:15299004-Mutagenesis, Site-Directed, pubmed-meshheading:15299004-Nerve Tissue Proteins, pubmed-meshheading:15299004-Peptide Fragments, pubmed-meshheading:15299004-Polymerase Chain Reaction, pubmed-meshheading:15299004-Potassium Channels, pubmed-meshheading:15299004-Protein Conformation, pubmed-meshheading:15299004-Recombinant Fusion Proteins, pubmed-meshheading:15299004-Sequence Deletion
pubmed:year
2004
pubmed:articleTitle
Dissecting the structural and functional roles of the S3-S4 linker of pacemaker (hyperpolarization-activated cyclic nucleotide-modulated) channels by systematic length alterations.
pubmed:affiliation
Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USa.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't