A nonapeptide to the putative F-actin binding site of annexin-II tetramer inhibits its calcium-dependent activation of actin filament bundling.
A synthetic nonapeptide, Val-Leu-Ile-Arg-Ile-Met-Val-Ser-Arg, corresponding to residues 286-294 of annexin-II tetramer (A-IIt), was shown to completely inhibit the Ca(2+)-dependent bundling of F-actin by this protein. The inhibitory effect of the nonapeptide required preincubation with F-actin and was reversed by the addition of excess A-IIt. Kinetic analysis suggested that the nonapeptide reduced the K(0.5) but not the Vmax of F-actin bundling. In contrast, addition of excess nonapeptide to A-IIt-bundled F-actin did not reverse F-actin bundle formation. Although the nonapeptide produced a dose-dependent inhibition of A-IIt-dependent F-actin bundling, the binding of A-IIt to F-actin was not affected. These results identify a domain of A-IIt that is involved in the bundling activity of the protein and suggest that this domain binds transiently with F-actin, resulting in activation of the bundling activity of A-IIt.
Jones
P G
PG
Department of Medical Biochemistry, University of Calgary, Alberta, Canada.
Moore
G J
GJ
Waisman
D M
DM
D000199:Actins / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D017302:Annexins; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D007700:Kinetics; D008168:Lung / Q000378:metabolism; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*
D000199:Actins; D017302:Annexins; D002135:Calcium-Binding Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009842:Oligopeptides; D010446:Peptide Fragments; D002118:Calcium