Institute for Biochemistry and Pathobiochemistry, Department of Systems Biology, Faculty of Medicine, Ruhr University of Bochum, 44780 Bochum, Germany.
Munich Center for Integrated Protein Science at Chair of Biomolecular NMR, Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
J Mol Biol. 2021 Mar 5;433(5):166765. doi: 10.1016/j.jmb.2020.166765. Epub 2021 Jan 21.
Human PEX14 plays a dual role as docking protein in peroxisomal protein import and as peroxisomal anchor for microtubules (MT), which relates to peroxisome motility. For docking, the conserved N-terminal domain of PEX14 (PEX14-NTD) binds amphipathic alpha-helical ligands, typically comprising one or two aromatic residues, of which human PEX5 possesses eight. Here, we show that the PEX14-NTD also binds to microtubular filaments in vitro with a dissociation constant in nanomolar range. PEX14 interacts with two motifs in the C-terminal region of human ß-tubulin. At least one of the binding motifs is in spatial proximity to the binding site of microtubules (MT) for kinesin. Both PEX14 and kinesin can bind to MT simultaneously. Notably, binding of PEX14 to tubulin can be prevented by its association with PEX5. The data suggest that PEX5 competes peroxisome anchoring to MT by occupying the ß-tubulin-binding site of PEX14. The competitive correlation of matrix protein import and motility may facilitate the homogeneous dispersion of peroxisomes in mammalian cells.
人 PEX14 作为蛋白在过氧化物酶体蛋白导入中的对接蛋白和微管（MT）的过氧化物酶体锚，与过氧化物酶体的运动有关。对于对接，PEX14 的保守 N 端结构域（PEX14-NTD）结合两亲性 α 螺旋配体，通常包含一个或两个芳香族残基，其中人 PEX5 具有八个。在这里，我们表明 PEX14-NTD 也在体外与微管丝状纤维以纳摩尔范围的离解常数结合。PEX14 与人 β-微管蛋白的 C 端区域的两个基序相互作用。至少一个结合基序与驱动蛋白结合微管（MT）的结合位点在空间上接近。PEX14 和驱动蛋白都可以同时结合到 MT 上。值得注意的是，PEX14 与 PEX5 的关联可以防止其与微管蛋白结合。数据表明，PEX5 通过占据 PEX14 的 β-微管蛋白结合位点来竞争过氧化物酶体锚定到 MT。基质蛋白导入和运动的竞争相关性可能促进哺乳动物细胞中过氧化物酶体的均匀分散。
