Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
Mol Microbiol. 2012 Apr;84(2):310-23. doi: 10.1111/j.1365-2958.2012.08024.x. Epub 2012 Mar 15.
Sexual development in fungi is a complex process involving the generation of new cell types and tissues - an essential step for all eukaryotic life. The characterization of sterile mutants in the ascomycete Sordaria macrospora has led to a number of proteins involved in sexual development, but a link between these proteins is still missing. Using a combined tandem-affinity purification/mass spectrometry approach, we showed in vivo association of developmental protein PRO22 with PRO11, homologue of mammalian striatin, and SmPP2AA, scaffolding subunit of protein phosphatase 2A. Further experiments extended the protein network to the putative kinase activator SmMOB3, known to be involved in sexual development. Extensive yeast two-hybrid studies allowed us to pinpoint functional domains involved in protein-protein interaction. We show for the first time that a number of already known factors together with new components associate in vivo to form a highly conserved multi-subunit complex. Strikingly, a similar complex has been described in humans, but the function of this so-called striatin interacting phosphatase and kinase (STRIPAK) complex is largely unknown. In S. macrospora, truncation of PRO11 and PRO22 leads to distinct defects in sexual development and cell fusion, indicating a role for the fungal STRIPAK complex in both processes.
真菌的性发育是一个复杂的过程，涉及新的细胞类型和组织的产生 - 这是所有真核生物生命的必要步骤。在子囊菌 Sordaria macrospora 中无菌突变体的特征导致了许多参与性发育的蛋白质，但这些蛋白质之间仍然缺乏联系。使用组合串联亲和纯化/质谱分析方法，我们在体内显示了发育蛋白 PRO22 与 PRO11、哺乳动物 striatin 的同源物以及蛋白磷酸酶 2A 的支架亚基 SmPP2AA 的关联。进一步的实验将蛋白质网络扩展到已知参与性发育的假定激酶激活剂 SmMOB3。广泛的酵母双杂交研究使我们能够确定参与蛋白质-蛋白质相互作用的功能结构域。我们首次表明，许多已知的因子与新的成分一起在体内形成一个高度保守的多亚基复合物。引人注目的是，在人类中已经描述了类似的复合物，但这个所谓的 striatin 相互作用的磷酸酶和激酶（STRIPAK）复合物的功能在很大程度上是未知的。在 S. macrospora 中，PRO11 和 PRO22 的截断导致性发育和细胞融合的明显缺陷，表明真菌 STRIPAK 复合物在这两个过程中都起作用。
