Characterization of the Calmodulin binding on the Transient receptor potential cation channel TRP M5

J. Bílý, B. Holakovská, J. Teisinger

Department of Protein Structures, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, Praha 4, 142 20

Transient receptor potential (TRP) proteins are a diverse family of proteins with structural features typical of ion channels. TRPM5, a member of the TRPM subfamily, plays an important role in taste receptors. TRPM5 is a monovalent-specific, nonselective cation channel that carries Na⁺, K⁺, but not Ca²⁺ ions. It is directly activated by Ca²⁺ , but activation mechanism remains controversial.

On basis of a comparison of the similarity with TRPM4 and Calmodulin target database, there have been identified several binding sites.

To detect Calmodulin binding site we used anisotropy measurements between Calmodulin and short peptides of the TRPM5 labeled with fluorescent probe. Short peptides were designed based on amino acids sequence of the TRPM5, also mutant version of peptides with replaced amino acids with neutral alanine to determine role of the residues in Calmodulin binding.

This work was supported by the Grant Agency of the Academy of Sciences of the Czech Republic (GAAV IAA600110701, GACR 303/07/0915) project (No. H148), Centre of Neurosciences No. LC554 The Ministry of Education, Youth and Sports of the Czech Republic, Research project No. AV0Z