S-100 (alpha and beta) binding peptide (TRTK-12) blocks S-100/GFAP interaction: identification of a putative S-100 target epitope within the head domain of GFAP.
Alignment of previously characterized S-100 (alpha and beta)-binding peptides (J. Biol. Chem. 270, 14651-14658) has enabled the identification of a putative S-100 target epitope within the head domain of glial fibrillary acidic protein (GFAP). The capacity of a known peptide inhibitor of S-100 protein (TRTK-12), homologous to this region, to perturb the interaction of S-100 (alpha and beta) and GFAP (J. Biol. Chem 268, 12669-12674) was investigated. Fluorescence spectrophotometry and chemical cross-linking analyses determined TRTK-12 to disrupt S-100:GFAP interaction in a dose- and Ca(2+_dependent manner. TRTK-12 also inhibited S-100's ability to block GFAP assembly and to mediate disassembly of preformed glial filaments. Each of these events was strictly dependent upon the presence of calcium and inhibitory peptide, maximal inhibition occurring at a concentration of TRTK-12 equivalent to the molar amount of S-100 monomer present. Together with our recent report demonstrating TRTK-12 also blocks the interaction of S-100 protein with the actin capping protein, CapZ, these results suggest TRTK-12 functions as a pleiotropic inhibitor of S-100 function. Availability of a functional inhibitor of S-100 will assist the further characterization of S-100 protein function in vitro and in vivo. Moreover, this report provides additional evidence supportive of a role for S-100 as a multi-faceted regulator of cytoskeletal integrity.
Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy.
R
R
Bianchi
M
M
Garbuglia
M
M
Verzini
I
I
Giambanco
V V
VV
Ivanenkov
R V
RV
Dimlich
G A
GA
Jamieson
R
R
Donato
D015081:2-Naphthylamine / Q000031:analogs & derivatives; D000595:Amino Acid Sequence; D000818:Animals; D015415:Biomarkers; D002118:Calcium / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002417:Cattle; D003432:Cross-Linking Reagents; D000939:Epitopes / Q000032:analysis*; D005456:Fluorescent Dyes; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009414:Nerve Growth Factors / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment; D013050:Spectrometry, Fluorescence / Q000379:methods; D013388:Succinimides; D014783:Viscosity
D015415:Biomarkers; D002135:Calcium-Binding Proteins; D003432:Cross-Linking Reagents; D000939:Epitopes; D005456:Fluorescent Dyes; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; C030564:S-100 calcium-binding protein alpha subunit; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D013388:Succinimides; C038518:acrylodan; D015081:2-Naphthylamine; D002118:Calcium; C019358:disuccinimidyl suberate