The role of the fungal STRIPAK complex in hyphal fusion and sexual development

真菌 STRIPAK 复合物在菌丝融合和性发育中的作用

• 批准号: 429272002
• 负责人: Professorin Dr. Stefanie Pöggeler
• 金额: --
• 依托单位: Abteilung Genetik eukaryotischer Mikroorganismen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/429272002?language=en
• 关键词: role; fungal; STRIPAK; complex; hyphal

Striatin-interacting phosphatase and kinase (STRIPAK) complex is conserved in fungi and animals. In the filamentous ascomycete Sordaria macrospora, STRIPAK complex has been found to be essential for hyphal fusion and fruiting-body development. The STRIPAK orthologues in S. macrospora are PRO11 (striatin), PRO22 (STRIP1/2), PRO45 (SLMAP), the serine-threonine phosphatase scaffolding subunit PP2AA, catalytic subunit SmPP2Ac1, and kinase activator SmMOB3. Unlike mammals, fungi comprise only one striatin gene and are therefore good models to study the cellular function of the STRIPAK complex. Recently, we performed PRO11 and SmMOB3 pull-down experiments coupled to liquid chromatography and mass spectrometry (LCMS) and analyzed the LCMS data for putative interaction partners. An uncharacterized protein was identified as putative PRO11 interaction partner with very high confidence, and was named STRIPAK complex interactor 1 (SCI1). SCI1 is an orthologue of small coiled-coil (CC) domain(s) containing proteins found in STRIPAK complexes in yeasts, fruit fly, and mammals. Deletion of sci1 revealed its role in cell-cell fusion and sexual development in S. macrospora, and SCI1 was found to interact and co-localize with other STRIPAK components at the nuclear envelope in vivo. Thus, SCI1 can be considered as a core component of the S. macrospora STRIPAK complex and we proved that our proteomics approach is useful to identify STRIPAK components and effectors. Further detailed analysis of LCMS data from PRO11, SmMOB3, and SCI1 pull-down experiments showed significant enrichment of three proteins of the nuclear pore complex, the activator of germinal center kinases MO25/HYM1, and four proteins involved in phospholipid biosynthesis and transport. These data suggested that the STRIPAK complex may play a role in kinase signaling pathways and in phospholipid signaling. Moreover, nuclear pore complex proteins may act as anchors that link the STRIPAK complex to the nuclear envelope. Alternatively, components of the nuclear pore complex may be regulated by phosphorylation and dephosphorylation events via STRIPAK associated kinases and the PP2A phosphatase. Thus, by studying these new interaction partners of the STRIPAK complex, we aim to understand the role of STRIPAK complex in sexual development and cell fusion in fungi. Beside, these investigations may also help to decipher the function of STRIPAK complexes in higher eukaryotes.

纹状蛋白相互作用磷酸酶和激酶（STRIPAK）复合物在真菌和动物中是保守的。在丝状子囊菌Sordaria macrospora中，STRIPAK复合物被发现对菌丝融合和子实体发育至关重要。在大孢子菌中，STRIPAK的同源物有PRO11 （striatin）、PRO22 （STRIP1/2）、PRO45 （SLMAP）、丝氨酸-苏氨酸磷酸酶支架亚基PP2AA、催化亚基SmPP2Ac1和激酶激活剂SmMOB3。与哺乳动物不同，真菌只包含一个纹状蛋白基因，因此是研究STRIPAK复合物细胞功能的良好模型。最近，我们将PRO11和SmMOB3下拉实验与液相色谱和质谱（LCMS）相结合，并对LCMS数据进行了分析，以确定可能的相互作用伙伴。一个未知的蛋白被确定为PRO11的推定相互作用伙伴，并被命名为STRIPAK复合物相互作用因子1 （SCI1）。SCI1是酵母、果蝇和哺乳动物中STRIPAK复合物中含有的小螺旋线圈（CC）结构域的同源物。sci1的缺失揭示了其在大孢子s细胞融合和性发育中的作用，并且在体内发现sci1与其他STRIPAK成分在核膜上相互作用和共定位。因此，SCI1可以被认为是S. macrospora STRIPAK复合物的核心组分，我们证明了我们的蛋白质组学方法可以用于鉴定STRIPAK组分和效应物。进一步对PRO11、SmMOB3和SCI1下拉实验的LCMS数据进行详细分析，发现核孔复合体的3个蛋白、生发中心激酶MO25/HYM1的激活剂以及参与磷脂生物合成和运输的4个蛋白显著富集。这些数据表明，STRIPAK复合物可能在激酶信号通路和磷脂信号通路中发挥作用。此外，核孔复合物蛋白可能作为将STRIPAK复合物连接到核膜的锚点。另外，核孔复合物的组分可能通过STRIPAK相关激酶和PP2A磷酸酶受到磷酸化和去磷酸化事件的调节。因此，通过研究这些新的STRIPAK复合物的相互作用伙伴，我们旨在了解STRIPAK复合物在真菌性发育和细胞融合中的作用。此外，这些研究也可能有助于破译STRIPAK复合物在高等真核生物中的功能。