A novel system for expressing toxic actin mutants in Dictyostelium and purification and characterization of a dominant lethal yeast actin mutant

Taro Q.P. Noguchi, Noriko Kanzaki, Hironori Ueno, Keiko Hirose, Taro Q.P. Uyeda*

*この研究の対応する著者

研究成果: Article査読

32 被引用数 (Scopus)

抄録

We have developed a novel system for expressing recombinant actin in Dictyostelium. In this system, the C terminus of actin is fused to thymosin β via a glycine-based linker. The fusion protein is purified using a His tag attached to the thymosin β moiety and then cleaved by chymotrypsin immediately after the native final residue of actin to yield intact actin. Wild-type actin prepared in this way was functionally normal in terms of its polymerization kinetics and muscle myosin-mediated motility. We expected that this system would be particularly useful for expressing toxic actin mutants, because the actin moiety of the fusion protein is unlikely to interact with the actin cytoskeleton of the host cells. We therefore chose to express the E206A/R207A/E208A mutant, which appears to be dominant lethal in yeast, as a model case of a toxic actin mutant that is difficult to express. We found that the E206A/R207A/E208A mutant could be expressed and purified with a yield comparable to the wild-type molecule (3-4 mg/20 g cells), even though green fluorescent protein-fused actin carrying the E206A/R207A/E208A mutation was expressed at a much lower level than wild-type actin. Purified E206A/R207A/E208A actin did not polymerize, even in the presence of muscle actin; however, it accelerated polymerization of muscle actin and inhibited the nucleating and severing activities of gelsolin. Given that the location of the substituted residues is near the pointed end face of the mutant, we suggest that E206A/R207A/E208A actin behaves like a weak pointed end-capping protein that perturbs the actin cytoskeleton of the host cells.

本文言語English
ページ(範囲)27721-27727
ページ数7
ジャーナルJournal of Biological Chemistry
282
38
DOI
出版ステータスPublished - 2007 9 21
外部発表はい

ASJC Scopus subject areas

  • 生化学
  • 分子生物学
  • 細胞生物学

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