Two Novel Heat-Soluble Protein Families Abundantly Expressed in an Anhydrobiotic Tardigrade

Ayami Yamaguchi, Sae Tanaka, Shiho Yamaguchi, Hirokazu Kuwahara, Chizuko Takamura, Shinobu Imajoh-Ohmi, Daiki D. Horikawa, Atsushi Toyoda, Toshiaki Katayama, Kazuharu Arakawa, Asao Fujiyama, Takeo Kubo, Takekazu Kunieda

研究成果: Article査読

58 被引用数 (Scopus)

抄録

Tardigrades are able to tolerate almost complete dehydration by reversibly switching to an ametabolic state. This ability is called anhydrobiosis. In the anhydrobiotic state, tardigrades can withstand various extreme environments including space, but their molecular basis remains largely unknown. Late embryogenesis abundant (LEA) proteins are heat-soluble proteins and can prevent protein-aggregation in dehydrated conditions in other anhydrobiotic organisms, but their relevance to tardigrade anhydrobiosis is not clarified. In this study, we focused on the heat-soluble property characteristic of LEA proteins and conducted heat-soluble proteomics using an anhydrobiotic tardigrade. Our heat-soluble proteomics identified five abundant heat-soluble proteins. All of them showed no sequence similarity with LEA proteins and formed two novel protein families with distinct subcellular localizations. We named them Cytoplasmic Abundant Heat Soluble (CAHS) and Secretory Abundant Heat Soluble (SAHS) protein families, according to their localization. Both protein families were conserved among tardigrades, but not found in other phyla. Although CAHS protein was intrinsically unstructured and SAHS protein was rich in β-structure in the hydrated condition, proteins in both families changed their conformation to an α-helical structure in water-deficient conditions as LEA proteins do. Two conserved repeats of 19-mer motifs in CAHS proteins were capable to form amphiphilic stripes in α-helices, suggesting their roles as molecular shield in water-deficient condition, though charge distribution pattern in α-helices were different between CAHS and LEA proteins. Tardigrades might have evolved novel protein families with a heat-soluble property and this study revealed a novel repertoire of major heat-soluble proteins in these anhydrobiotic animals.

本文言語English
論文番号e44209
ジャーナルPloS one
7
8
DOI
出版ステータスPublished - 2012 8 28
外部発表はい

ASJC Scopus subject areas

  • 生化学、遺伝学、分子生物学(全般)
  • 農業および生物科学(全般)
  • 一般

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