Characterization of an Intermediate Filament Protein from the Platyhelminth, Dugesia japonica

Author(s): Akiko Yamamoto, Ken-ichiro Matsunaga, Toyoaki Anai, Hitoshi Kawano, Toshihisa Ueda, Toshihiko Matsumoto, Shoji Ando*.

Journal Name: Protein & Peptide Letters

Volume 27 , Issue 5 , 2020

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Graphical Abstract:


Background: Intermediate Filaments (IFs) are major constituents of the cytoskeletal systems in animal cells.

Objective: To gain insights into the structure-function relationship of invertebrate cytoplasmic IF proteins, we characterized an IF protein from the platyhelminth, Dugesia japonica, termed Dif-1.

Methods: cDNA cloning, in situ hybridization, immunohistochemical analysis, and IF assembly experiments in vitro using recombinant Dif-1, were performed for protein characterization.

Results: The structure deduced from the cDNA sequence showed that Djf-1 comprises 568 amino acids and has a tripartite domain structure (N-terminal head, central rod, and C-terminal tail) that is characteristic of IF proteins. Similar to nuclear IF lamins, Djf-1 contains an extra 42 residues in the coil 1b subdomain of the rod domain that is absent from vertebrate cytoplasmic IF proteins and a nuclear lamin-homology segment of approximately 105 residues in the tail domain; however, it contains no nuclear localization signal. In situ hybridization analysis showed that Djf-1 mRNA is specifically expressed in cells located within the marginal region encircling the worm body. Immunohistochemical analysis showed that Djf-1 protein forms cytoplasmic IFs located close to the microvilli of the cells. In vitro IF assembly experiments using recombinant proteins showed that Djf-1 alone polymerizes into IFs. Deletion of the extra 42 residues in the coil 1b subdomain resulted in the failure of IF formation.

Conclusion: Together with data from other histological studies, our results suggest that Djf- 1 is expressed specifically in anchor cells within the glandular adhesive organs of the worm and that Djf-1 IFs may play a role in protecting the cells from mechanical stress.

Keywords: Intermediate filament, molecular evolution, planarian, adhesive organ, structure-function relationship, anchor cells.

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Article Details

Year: 2020
Page: [432 - 446]
Pages: 15
DOI: 10.2174/0929866526666191025102902
Price: $65

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