Characterization of the S100A1 protein binding site on TRPC6 C-terminus

PLoS One. 2013 May 3;8(5):e62677. doi: 10.1371/journal.pone.0062677. Print 2013.

Abstract

The transient receptor potential (TRP) protein superfamily consists of seven major groups, among them the "canonical TRP" family. The TRPC proteins are calcium-permeable nonselective cation channels activated after the emptying of intracellular calcium stores and appear to be gated by various types of messengers. The TRPC6 channel has been shown to be expressed in various tissues and cells, where it modulates the calcium level in response to external signals. Calcium binding proteins such as Calmodulin or the family of S100A proteins are regulators of TRPC channels. Here we characterized the overlapping integrative binding site for S100A1 at the C-tail of TRPC6, which is also able to accomodate various ligands such as Calmodulin and phosphatidyl-inositol-(4,5)-bisphosphate. Several positively charged amino acid residues (Arg852, Lys856, Lys859, Arg860 and Arg864) were determined by fluorescence anisotropy measurements for their participation in the calcium-dependent binding of S100A1 to the C terminus of TRPC6. The triple mutation Arg852/Lys859/Arg860 exhibited significant disruption of the binding of S100A1 to TRPC6. This indicates a unique involvement of these three basic residues in the integrative overlapping binding site for S100A1 on the C tail of TRPC6.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Anisotropy
  • Binding Sites
  • Calcium / chemistry
  • Circular Dichroism
  • Humans
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Structure, Secondary
  • S100 Proteins / chemistry*
  • TRPC Cation Channels / chemistry*
  • TRPC Cation Channels / genetics
  • TRPC6 Cation Channel

Substances

  • S100 Proteins
  • S100A1 protein
  • TRPC Cation Channels
  • TRPC6 Cation Channel
  • TRPC6 protein, human
  • Calcium

Grant support

This work was supported by grant 301/10/1159 of the Grant Agency of the Czech Republic, grant P205/10/P308 of the Grant Agency of the Czech Republic and from institutional project of the Institute of Physiology (RVO: 67985823) and institutional project of the Institute of Microbiology, Academy of Sciences of the Czech Republic (RVO: 61388971). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.