Purification and properties of filamin, and actin binding protein from chicken gizzard.
Filamin, a protein recently identified in chicken gizzard (Wang, K., Ash, F., and Singer, S. J. (1975) Proc. Natl. Acad. Sci. U. S. A. 72, 4483-4486), has been purified free of other components and its molecular properties have been examined. Filamin has a sedimentation constant (S020,w) of 8.86 S and a partial specific volume of 0.734 ml/g. Sedimentation equilibrium experiments give a value of 498,000 for the molecular weight of native filamin. From these data a frictional ratio of 2.32 has been calculated. On sodium dodecyl sulfate gel electrophoresis, filamin migrates as a single protein band with an estimated molecular weight of 240,000. Filamin is a soluble protein and under a variety of conditions tested does not by itself form filaments or precipitate from solution. However, filamin binds to rabbit skeletal muscle F-actin, and the complex is readily sedimented by centrifugation to yield a gelatinous pellet containing actin and filamin. These results indicate that filamin is a dimeric protein with a moderate degree of asymmetry that binds to actin. The results also suggest that the distribution of filamin in cells is derived from its interaction with polymerized actin.
D000199:Actins / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002645:Chickens; D003285:Contractile Proteins / Q000302:isolation & purification / Q000378:metabolism; D005895:Gizzard, Avian / Q000378:metabolism*; D008970:Molecular Weight; D011485:Protein Binding
D000199:Actins; D000596:Amino Acids; D003285:Contractile Proteins