Major epiplasmic proteins of ciliates are articulins: cloning, recombinant expression, and structural characterization

Article Article scientifique Article Major epiplasmic proteins of ciliates are articulins: cloning, recombinant expression, and structural characterization eng 1995-09 author Huttenlauch-Stick Irmgard Thekla 39564 author Geisler Norbert author Plessmann Uwe author Peck Robert 25553 author Weber Klaus-Peter 45959 author Stick Reimer 39326 1401-1412 10.1083/jcb.130.6.1401 0021-9525 The cytoskeleton of certain protists comprises an extensive membrane skeleton, the epiplasm, which contributes to the cell shape and patterning of the species-specific cortical architecture. The isolated epiplasm of the ciliated protist Pseudomicrothorax dubius consists of two major groups of proteins with molecular masses of 78-80 kD and 11-13 kD, respectively. To characterize the structure of these proteins, peptide sequences of two major polypeptides (78-80 kD) as well as a cDNA representing the entire coding sequence of a minor and hitherto unidentified component (60 kD; p60) of the epiplasm have been determined. All three polypeptides share sequence similarities. They contain repeated valine- and proline-rich motifs of 12 residues with the consensus VPVP--V-V-V-. In p60 the central core domain consists of 24 tandemly repeated VPV motifs. Within the repeat motifs positively and negatively charged residues, when present, show an alternating pattern in register with the V and P positions. Recombinant p60 was purified in 8 M urea and dialyzed against buffer. Infrared spectroscopic measurements indicate 30% β-sheet. Electron microscopy reveals short filamentous polymers with a rather homogenous diameter (~15-20 nm), but variable lengths. The small polymers form thicker filaments, ribbons, and larger sheets or tubes. A core domain similar to that of P. dubius p60 is also found in the recently described epiplasmic proteins of the flagellate Euglena, the so-called articulins. Our results show that the members of this protein family are not restricted to flagellates, but are also present in the distantly related ciliates where they are major constituents of the epiplasm. Comparison of flagellate and ciliate articulins highlights common features of this novel family of cytoskeletal proteins. Dewey 590 44 Département de génétique et évolution 162 false The Journal of cell biology 130 6 e5172322-1024-4ac8-96e2-2e4277f89db8 Article (Published version) Public HUTTENLAUCH_TJCB_19951412.pdf 4960762 application/pdf CC BY-NC-SA openAccess Faculté des sciences / Section de biologie / Département de génétique et évolution

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Major epiplasmic proteins of ciliates are articulins: cloning, recombinant expression, and structural characterization	The Journal of cell biology			1995	121	57

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Weber, Klaus-Peter