Isolation of an actin polymerization stimulator from bovine thyroid plasma membranes

• Published in: Biochemical and biophysical research communications Vol. 111; no. 2; pp. 415 - 423
• Main Authors: Tawata, Masato, Kobayashi, Ryoji, Mace, Myles L., Nielsen, Thor B., Field, James B.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.1983
• Subjects: actin polymerization activator; Actins - metabolism; Animals; Cattle; Cell Membrane - analysis; Chromatography, Affinity; Cytochalasin B - metabolism; Deoxyribonuclease I; Electrophoresis, Polyacrylamide Gel; Endodeoxyribonucleases - metabolism; Membrane Proteins - isolation & purification; Microscopy, Electron; Molecular Weight; plasma membranes; Polymers - metabolism; thyroid; Thyroid Gland - analysis
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(83)90322-4

An actin polymerization stimulator was purified from bovine thyroid plasma membranes by DNase I affinity column chromatography. Although the molecular weight of the protein was about 42,000 (42K) by sodium dodecyl sulfate polyacrylamide gel electrophoresis, it did not comigrate with actin. In the presence of 30 mM KCl, the 42K protein facilitated formation of actin filaments when analyzed by a centrifugation method, accelerated the initial phase of actin polymerization as measured in an Ostwald viscometer and increased the length of filaments as shown by electron microscopy. The 42K protein also accelerated the initial phase of actin polymerization in the presence of 100 mM KCl and 2 mM MgCl 2 but did not affect the final viscosity. The effect of the 42K protein was diminished by 5 uM cytochalasin B or 1 uM cytochalasin D. This 42K protein may anchor actin filaments onto the thyroid plasma membrane.