Studies on the interaction between actin and cofilin purified by a new method.
Cofilin is a 21,000-Mr actin-binding protein that widely exists in mammalian tissues. (1) A new purification procedure for porcine brain cofilin has been developed that involves (NH4)2SO4 fractionation and sequential chromatographies on Toyo Pearl and butyl-Toyo Pearl hydrophobic columns, hydroxyapatite, phosphocellulose and Sephadex G-75 gel-filtration columns. The purified cofilin bound to F-actin and increased the amount of G-actin to a limited extent, as previously reported [Nishida, Maekawa & Sakai (1984) Biochemistry 23, 5307-5313]. (2) The binding of cofilin to F-actin was scarcely affected by Mg2+, Ca2+ or by calmodulin. However, the binding was diminished by increasing concentrations of KCl, but was only slightly affected by temperature. (3) Cofilin and either alpha-actinin or filamin could bind to F-actin simultaneously with some competition, but the binding of caldesmon to F-actin was markedly inhibited by cofilin. Phalloidin inhibited the binding of cofilin to F-actin, and protected F-actin from depolymerization by cofilin.
Yonezawa
N
N
Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
Nishida
E
E
Maekawa
S
S
Sakai
H
H
D051339:Actin Depolymerizing Factors; D000185:Actinin / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D002148:Calmodulin-Binding Proteins / Q000378:metabolism; D002853:Chromatography, Liquid; D003285:Contractile Proteins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D064448:Filamins; D008274:Magnesium / Q000494:pharmacology; D008840:Microfilament Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010590:Phalloidine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects
D051339:Actin Depolymerizing Factors; D000199:Actins; D002148:Calmodulin-Binding Proteins; D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D000185:Actinin; D010590:Phalloidine; D011189:Potassium Chloride; D008274:Magnesium; D002118:Calcium