title: Characterization of the S100A1 protein binding site on TRPC6 C-terminus.
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.
authors.affiliation: Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Bily
authors.forename: Lenka
authors.initials: L
authors.lastname: Grycova
authors.forename: Blanka
authors.initials: B
authors.lastname: Holendova
authors.forename: Michaela
authors.initials: M
authors.lastname: Jirku
authors.forename: Hana
authors.initials: H
authors.lastname: Janouskova
authors.forename: Kristyna
authors.initials: K
authors.lastname: Bousova
authors.forename: Jan
authors.initials: J
authors.lastname: Teisinger
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D016880:Anisotropy; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry; D002942:Circular Dichroism; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D017433:Protein Structure, Secondary; D009418:S100 Proteins / Q000737:chemistry*; D050052:TRPC Cation Channels / Q000737:chemistry* / Q000235:genetics; D000074287:TRPC6 Cation Channel
chemical_list: D009418:S100 Proteins; C110294:S100A1 protein; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; D002118:Calcium