Interaction of S100a0 protein with the actin capping protein, CapZ: characterization of a putative S100a0 binding site in CapZ alpha-subunit.
S100a0, a Ca2+-binding protein expressed predominantly in cardiac and skeletal muscle tissues, was demonstrated by chemical cross-linking to interact in a Ca2+ -dependent manner with the actin capping protein CapZ. TRTK-12, a peptide contained within the COOH-terminal region of CapZalpha, inhibited S100a0: CapZ interaction in a dose-dependent manner. TRTK-12 was shown by cross-linking to bind S100a0 in the presence of Ca2+, and by fluorescence spectrophotometry to interact in a saturable manner with the anionic phospholipid and a regulator of CapZ activity, phosphatidylinositol 4-monophosphate; but not with the neutral phospholipid, phosphatidylcholine. These data suggest S100a0 and polyphosphoinositides bind to the same COOH-terminal region of CapZalpha, thus potentially modulating CapZ activity.
Ivanenkov
V V
VV
Department of Emergency Medicine, University of Cincinnati College of Medicine, Ohio 45267, USA.
Dimlich
R V
RV
Jamieson
G A
GA
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D051347:CapZ Actin Capping Protein; D002417:Cattle; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D011485:Protein Binding; D009418:S100 Proteins / Q000378:metabolism*
D051347:CapZ Actin Capping Protein; D008840:Microfilament Proteins; D009124:Muscle Proteins; D018129:Phosphatidylinositol Phosphates; D009418:S100 Proteins; C037178:phosphatidylinositol 4-phosphate; D002118:Calcium