A synthetic peptide that prevents cAMP regulation in mammalian hyperpolarization-activated cyclic nucleotide-gated (HCN) channels

Elife. 2018 Jun 20;7:e35753. doi: 10.7554/eLife.35753.


Binding of TRIP8b to the cyclic nucleotide binding domain (CNBD) of mammalian hyperpolarization-activated cyclic nucleotide-gated (HCN) channels prevents their regulation by cAMP. Since TRIP8b is expressed exclusively in the brain, we envisage that it can be used for orthogonal control of HCN channels beyond the central nervous system. To this end, we have identified by rational design a 40-aa long peptide (TRIP8bnano) that recapitulates affinity and gating effects of TRIP8b in HCN isoforms (hHCN1, mHCN2, rbHCN4) and in the cardiac current If in rabbit and mouse sinoatrial node cardiomyocytes. Guided by an NMR-derived structural model that identifies the key molecular interactions between TRIP8bnano and the HCN CNBD, we further designed a cell-penetrating peptide (TAT-TRIP8bnano) which successfully prevented β-adrenergic activation of mouse If leaving the stimulation of the L-type calcium current (ICaL) unaffected. TRIP8bnano represents a novel approach to selectively control HCN activation, which yields the promise of a more targeted pharmacology compared to pore blockers.

Keywords: HCN; cAMP; cardiac pacemaker; molecular biophysics; mouse; structural biology.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Calcium Channels, L-Type / chemistry
  • Calcium Channels, L-Type / genetics
  • Calcium Channels, L-Type / metabolism
  • Cell-Penetrating Peptides / chemistry
  • Cell-Penetrating Peptides / genetics
  • Cell-Penetrating Peptides / metabolism
  • Cyclic AMP / chemistry*
  • Cyclic AMP / metabolism
  • Gene Expression
  • HEK293 Cells
  • Humans
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / chemistry*
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / genetics
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Molecular Docking Simulation
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / drug effects*
  • Myocytes, Cardiac / metabolism
  • Patch-Clamp Techniques
  • Peptides / chemical synthesis
  • Peptides / pharmacology*
  • Peroxins / chemistry
  • Peroxins / genetics
  • Peroxins / metabolism
  • Potassium Channels / chemistry*
  • Potassium Channels / genetics
  • Potassium Channels / metabolism
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Rabbits
  • Sinoatrial Node / cytology
  • Sinoatrial Node / drug effects
  • Sinoatrial Node / metabolism
  • tat Gene Products, Human Immunodeficiency Virus


  • Calcium Channels, L-Type
  • Cell-Penetrating Peptides
  • HCN1 protein, human
  • Hcn2 protein, mouse
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels
  • Membrane Proteins
  • Peptides
  • Peroxins
  • Pex5l protein, mouse
  • Potassium Channels
  • tat Gene Products, Human Immunodeficiency Virus
  • Cyclic AMP