Huttenlauch Irm, Stick Reimer
Max Planck Institute for Biophysical Chemistry, Department of Biochemistry, Am Fassberg 11, D-37077 Göttingen, Germany.
J Eukaryot Microbiol. 2003 Jan-Feb;50(1):15-8. doi: 10.1111/j.1550-7408.2003.tb00101.x.
The cortex of ciliates. dinoflagellates, and euglenoids comprises a unique structure called the epiplasm, implicated in pattern-forming processes of the cell cortex and in maintaining cell shape. Articulins, a novel class of cytoskeletal proteins, are major constituents of the epiplasm in the flagellate Euglena gracilis and the ciliate Pseudomicrothorax dubius. The hallmark of articulins is a core domain of repetitive motifs of alternating valine and proline residues, the VPV-motif. The VPV-motif repeats are 12 residues long. Positively and negatively charged residues segregate in register with valine and proline positions. The VPV-motif is unique to articulins. The terminal domains flanking the core are generally hydrophobic and contain a series of hexa- or heptapeptide repeats rich in glycine and hydrophobic residues. Using molecular and immunological tools we show that articulins are also present in the dinoflagellate Amphidinium carterae and the ciliates Paramecium tetraurelia and Paramecium caudatum, Tetrahymena pyriformis, and Euplotes aediculatus. Our analysis further shows that epiplasmins, a group of epiplasmic proteins first characterized in Paramecium, are also present in all these species. Moreover, we present evidence that epiplasmins and articulins represent two distinct classes of cytoskeletal proteins.
纤毛虫、甲藻和裸藻的皮层包含一种独特的结构，称为表质，它与细胞皮层的模式形成过程以及维持细胞形状有关。关节蛋白是一类新型的细胞骨架蛋白，是鞭毛虫纤细裸藻和纤毛虫 dubius 中表质的主要成分。关节蛋白的标志是由缬氨酸和脯氨酸残基交替组成的重复基序的核心结构域，即 VPV 基序。VPV 基序重复序列长度为 12 个残基。带正电荷和负电荷的残基与缬氨酸和脯氨酸的位置对齐排列。VPV 基序是关节蛋白所特有的。核心结构域两侧的末端结构域通常是疏水的，并且包含一系列富含甘氨酸和疏水残基的六肽或七肽重复序列。我们使用分子和免疫学工具表明，关节蛋白也存在于甲藻卡特亚扁藻以及纤毛虫四膜虫、尾草履虫、梨形四膜虫和艾氏游仆虫中。我们的分析进一步表明，表质蛋白是一类最初在草履虫中被鉴定的表质蛋白，在所有这些物种中也都存在。此外，我们提供证据表明表质蛋白和关节蛋白代表两类不同的细胞骨架蛋白。
