title: The characterization of a novel S100A1 binding site in the N-terminus of TRPM1.
abstract: Transient receptor potential melastatin-1 channel (TRPM1) is an important mediator of calcium influx into the cell that is expressed in melanoma and ON-bipolar cells. Similar to other members of the TRP channel family, the intracellular N- and C- terminal domains of TRPM1 are expected to play important roles in the modulation of TRPM1 receptor function. Among the most commonly occurring modulators of TRP channels are the cytoplasmically expressed calcium binding proteins calmodulin and S100 calcium-binding protein A1 (S100A1), but the interaction of TRPM1 with S100A1 has not been described yet. Here, using a combination of biophysical and bioinformatics methods, we have determined that the N-terminal L242-E344 region of TRPM1 is a S100A1 binding domain. We show that formation of the TRPM1/S100A1 complex is calcium-dependent. Moreover, our structural model of the complex explained data obtained from fluorescence spectroscopy measurements revealing that the complex formation is facilitated through interactions of clusters positively charged (K271A, R273A, R274A) and hydrophobic (L263A, V270A, L276A) residues at the N-terminus of TRPM1. Taken together, our data suggest a molecular mechanism for the potential regulation of TRPM1 by S100A1.
authors.affiliation: Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic.
authors.forename: Michaela
authors.initials: M
authors.lastname: Jirku
authors.affiliation: Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, 25250 Vestec, Czech Republic.
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Lansky
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Bednarova
authors.affiliation: Institute of Microbiology, Czech Academy of Sciences, 14220 Prague, Czech Republic; Faculty of Science, Charles University in Prague, 12843 Prague, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Sulc
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Monincova
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Majer
authors.affiliation: Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Vyklicky
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Vondrasek
authors.affiliation: Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Teisinger
authors.affiliation: Institute of Physiology, Czech Academy of Sciences, 14220 Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 16610 Prague, Czech Republic. Electronic address: kristyna.bousova@fgu.cas.cz.
authors.forename: Kristyna
authors.initials: K
authors.lastname: Bousova
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D062105:Molecular Docking Simulation; D011485:Protein Binding; D000072417:Protein Domains; D017433:Protein Structure, Secondary; D051381:Rats; D009418:S100 Proteins / Q000737:chemistry / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D009418:S100 Proteins; C110294:S100A1 protein; D050053:TRPM Cation Channels; C000624571:Trpm1 protein, rat; D002118:Calcium
keywords: Binding site; Calcium-binding protein S100A1; Circular dichroism; Molecular modeling; Steady-state fluorescence anisotropy; TRPM1 channel