Division of Glycoscience, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, 106 91 Stockholm, Sweden.
Biochem Biophys Res Commun. 2012 Jan 27;417(4):1248-53. doi: 10.1016/j.bbrc.2011.12.118. Epub 2012 Jan 3.
Some oomycetes, for instance Saprolegnia parasitica, are severe fish pathogens that cause important economic losses worldwide. Cellulose biosynthesis is a vital process for this class of microorganisms, but the corresponding molecular mechanisms are poorly understood. Of all cellulose synthesizing enzymes known, only some oomycete cellulose synthases contain a pleckstrin homology (PH) domain. Some human PH domains bind specifically to phosphoinositides, but most PH domains bind phospholipids in a non-specific manner. In addition, some PH domains interact with various proteins. Here we have investigated the function of the PH domain of cellulose synthase 2 from the oomycete Saprolegnia monoica (SmCesA2), a species closely related to S. parasitica. The SmCesA2 PH domain is similar to the C-terminal PH domain of the human protein TAPP1. It binds in vitro to phosphoinositides, F-actin and microtubules, and co-localizes with F-actin in vivo. Our results suggest a role of the SmCesA2 PH domain in the regulation, trafficking and/or targeting of the cell wall synthesizing enzyme.
有些卵菌，例如寄生卵菌，是严重的鱼类病原体，在全球范围内造成了重大的经济损失。纤维素生物合成是这类微生物的一个重要过程，但相应的分子机制还知之甚少。在所有已知的纤维素合成酶中，只有一些卵菌纤维素合酶含有pleckstrin 同源（PH）结构域。一些人类 PH 结构域特异性地结合磷酸肌醇，但大多数 PH 结构域以非特异性方式结合磷脂。此外，一些 PH 结构域与各种蛋白质相互作用。在这里，我们研究了卵菌单生卵菌（SmCesA2）纤维素合酶 2 的 PH 结构域的功能，该物种与寄生卵菌密切相关。SmCesA2 PH 结构域类似于人类蛋白 TAPP1 的 C 端 PH 结构域。它在体外与磷酸肌醇、F-肌动蛋白和微管结合，并在体内与 F-肌动蛋白共定位。我们的结果表明，SmCesA2 PH 结构域在细胞壁合成酶的调节、运输和/或靶向中起作用。
