Trafficking of L-type calcium channels mediated by the postsynaptic scaffolding protein AKAP79

J Biol Chem. 2002 Sep 13;277(37):33598-603. doi: 10.1074/jbc.M202476200. Epub 2002 Jul 11.

Abstract

Accurate calcium signaling requires spatial and temporal coordination of voltage-gated calcium channels (VGCCs) and a variety of signal transduction proteins. Accordingly, regulation of L-type VGCCs involves the assembly of complexes that include the channel subunits, protein kinase A (PKA), protein kinase A anchoring proteins (AKAPs), and beta2-adrenergic receptors, although the molecular details underlying these interactions remain enigmatic. We show here, by combining extracellular epitope splicing into the channel pore-forming subunit and immunoassays with whole cell and single channel electrophysiological recordings, that AKAP79 directly regulates cell surface expression of L-type calcium channels independently of PKA. This regulation involves a short polyproline sequence contained specifically within the II-III cytoplasmic loop of the channel. Thus we propose a novel mechanism whereby AKAP79 and L-type VGCCs function as components of a biosynthetic mechanism that favors membrane incorporation of organized molecular complexes in a manner that is independent of PKA phosphorylation events.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A Kinase Anchor Proteins
  • Adaptor Proteins, Signal Transducing*
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Biological Transport
  • Calcium Channels, L-Type / analysis
  • Calcium Channels, L-Type / chemistry
  • Calcium Channels, L-Type / metabolism*
  • Carrier Proteins / physiology*
  • Hemagglutinins
  • Humans
  • Molecular Sequence Data

Substances

  • A Kinase Anchor Proteins
  • AKAP5 protein, human
  • Adaptor Proteins, Signal Transducing
  • Calcium Channels, L-Type
  • Carrier Proteins
  • Hemagglutinins
  • L-type calcium channel alpha(1C)