Biochemical studies on the functions of cytoplasmic actin in non-muscle cells 非筋細胞におけるアクチン機能の生化学的研究

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著者

    • 石浦, 正寛 イシウラ, マサヒロ

書誌事項

タイトル

Biochemical studies on the functions of cytoplasmic actin in non-muscle cells

タイトル別名

非筋細胞におけるアクチン機能の生化学的研究

著者名

石浦, 正寛

著者別名

イシウラ, マサヒロ

学位授与大学

大阪大学

取得学位

理学博士

学位授与番号

甲第2117号

学位授与年月日

1978-09-30

注記・抄録

博士論文

14401甲第02117号

理学博士

Ehrlich ascites tumor cell extracts form a gel when warmed to 25 degrees C at pH 7.0 in sucrose solution, and the gel rapidly becomes a sol when cooled to 0 degrees C. This gel-sol transformation was studied quantitatively by determining the volume or the total protein of pellets of gel obtained by low-speed centrifugation. The gelation depended on nucleotide triphosphates, Mg2+, KCl, and a reducing agent. Gelation was inhibited reversibly by 0.5 microM free Ca2+, and 25--50 ng/ml of either cytochalasin B or D, but it was not affected by 10 mM colchicine. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that the gel was composed of six major proteins with mol wt greater than 300,000, 270,000, 89,000, 51,000, 48,000, and 42,000 daltons. The last component was identified as cell actin because it had the same molecular weight as muscle actin and bound with muscle myosin and tropomyosin. The role of actin in gelation was studied by use of actin-inhibitors. Gelation was inhibited by a chemically modified subfragment-1 of myosin, which binds with F-actin even in the presence of ATP, and by bovine pancreatic DNase I, which tightly binds with G- actin. Muscle G-actin neutralized the inhibitory effect of DNase I when added at an equimolar ratio to the latter, and it also restored gelation after its inhibition by DNase I. These findings suggest that gelation depends on actin. However, the extracts showed temperature- dependent, cytochalasin-sensitive, and Ca2+-regulated gelation as did the original extracts when the cell actin in the extracts was replaced by muscle actin, suggesting that components other than cell actin might be responsible for these characteristics of the gelation.

大阪大学

1978-09-30

04384

Ishiura, Masahiro; Okada, Yoshio. THE ROLE OF ACTIN IN TEMPERATURE-DEPENDENT GEL-SOL TRANSFORMATION OF EXTRACTS OF EHRLICH ASCITES TUMOR CELLS. Journal of Cell Biology. 1979. 80(2), p.465-480.

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各種コード

  • NII論文ID(NAID)
    500000304332
  • NII著者ID(NRID)
    • 8000000305151
  • 本文言語コード
    • eng
  • NDL書誌ID
    • 000007764105
  • データ提供元
    • 機関リポジトリ
    • NDL ONLINE
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