The Cav1.2 N terminus contains a CaM kinase site that modulates channel trafficking and function

Pflugers Arch. 2015 Apr;467(4):677-86. doi: 10.1007/s00424-014-1538-7. Epub 2014 May 28.

Abstract

The L-type voltage-gated calcium channel Cav1.2 and the calcium-activated CaM kinase cascade both regulate excitation transcription coupling in the brain. CaM kinase is known to associate with the C terminus of Cav1.2 in a region called the PreIQ-IQ domain, which also binds multiple calmodulin molecules. Here we identify and characterize a second CaMKII binding site in the N terminus of Cav1.2 that is formed by a stretch of four amino residues (cysteine-isoleucine-serine-isoleucine) and which regulates channel expression and function. By using live cell imaging of tsA-201 cells we show that GFP fusion constructs of the CaMKII binding region, termed N2B-II co-localize with mCherry-CaMKII. Mutating CISI to AAAA ablates binding to and colocalization with CaMKII. Cav1.2-AAAA channels show reduced cell surface expression in tsA-201 cells, but interestingly, display an increase in channel function that offsets the trafficking deficit. Altogether our data reveal that the proximal N terminus of Cav1.2 contains a CaMKII binding region which contributes to channel surface expression and function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Calcium Channels, L-Type / chemistry
  • Calcium Channels, L-Type / metabolism*
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism*
  • Cell Membrane / metabolism
  • HEK293 Cells
  • Humans
  • Molecular Sequence Data
  • Protein Binding
  • Protein Transport
  • Rats

Substances

  • Calcium Channels, L-Type
  • L-type calcium channel alpha(1C)
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2