The role of a voltage-dependent Ca2+ channel intracellular linker: a structure-function analysis

J Neurosci. 2012 May 30;32(22):7602-13. doi: 10.1523/JNEUROSCI.5727-11.2012.


Voltage-dependent calcium channels (VDCCs) allow the passage of Ca(2+) ions through cellular membranes in response to membrane depolarization. The channel pore-forming subunit, α1, and a regulatory subunit (Ca(V)β) form a high affinity complex where Ca(V)β binds to a α1 interacting domain in the intracellular linker between α1 membrane domains I and II (I-II linker). We determined crystal structures of Ca(V)β2 functional core in complex with the Ca(V)1.2 and Ca(V)2.2 I-II linkers to a resolution of 1.95 and 2.0 Å, respectively. Structural differences between the highly conserved linkers, important for coupling Ca(V)β to the channel pore, guided mechanistic functional studies. Electrophysiological measurements point to the importance of differing linker structure in both Ca(V)1 and 2 subtypes with mutations affecting both voltage- and calcium-dependent inactivation and voltage dependence of activation. These linker effects persist in the absence of Ca(V)β, pointing to the intrinsic role of the linker in VDCC function and suggesting that I-II linker structure can serve as a brake during inactivation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biophysics
  • Calcium / metabolism
  • Calcium Channels / chemistry*
  • Calcium Channels / genetics
  • Calcium Channels / metabolism*
  • Crystallography
  • Extracellular Fluid / physiology*
  • Ion Channel Gating / genetics
  • Ion Channel Gating / physiology*
  • Membrane Potentials / drug effects
  • Membrane Potentials / genetics
  • Microinjections
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation / genetics
  • Oocytes
  • Protein Conformation
  • Protein Structure, Secondary / genetics
  • Protein Structure, Tertiary / genetics
  • Rabbits
  • Regulatory Sequences, Nucleic Acid / genetics
  • Spectrum Analysis
  • Xenopus laevis


  • Calcium Channels
  • Calcium