1. A monovalent cation-sensitive actin-binding factor in a myeloid leukemia cell line
- Author
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Takashi Hashida, Kuniaki Takagi, Yasuo Ichikawa, and Kazuhiro Nagata
- Subjects
Paper ,Antigenicity ,Physiology ,Cell ,Peptide ,macromolecular substances ,Chromatography, DEAE-Cellulose ,Cell Line ,Potassium Chloride ,Mice ,medicine ,Animals ,Molecular Biology ,Gelsolin ,Actin ,chemistry.chemical_classification ,biology ,Binding protein ,Microfilament Proteins ,Collodion ,Skeletal muscle ,Cell Biology ,General Medicine ,biology.organism_classification ,Actina ,Actins ,Molecular Weight ,Microscopy, Electron ,medicine.anatomical_structure ,chemistry ,Leukemia, Myeloid ,Cell culture ,Immunology ,Biophysics ,Electrophoresis, Polyacrylamide Gel ,Carrier Proteins - Abstract
Cell extracts of a murine leukemia cell line, M1, apparently contain three kinds of actin-gelation factors; a filamin-like protein, and 38K-dimer and 105K-dimer proteins. Unlike gelation by the filamin-like protein, gelation by the latter two proteins is inhibited by low concentrations of KCl. Our study of the 38K protein has been reported elsewhere (Takagi, K. et al., J. Biochem. Tokyo 97, 605-616, 1985). We here describe the purification and characterization of the 105K protein. The 105K protein differs from the alpha-actinin group of proteins in its antigenicity, peptide components and Ca2+-insensitivity. The saturated binding ratio of the protein to purified skeletal muscle actin is 1:8; when this ratio exceeds 1:20, gelation takes place. This gelation is inhibited completely by the presence of 25 mM KCl. Electron microscopy revealed that, in the absence of KCl, the 105K protein/actin mixture forms short actin bundles that are accompanied by a meshwork of short single filaments. The presence of 25 mM KCl did not prevent actin-bundling, but the bundles became longer and the meshwork of short filaments was no longer present.
- Published
- 1985
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