Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel.
Centre for Scientific Imaging, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 7610000, Israel.
Mol Microbiol. 2018 Jun;108(6):641-660. doi: 10.1111/mmi.13954. Epub 2018 Apr 19.
The Neurospora crassa Mps One Binder (MOB) proteins MOB2A and MOB2B physically interact with the Nuclear Dbf2 Related (NDR) kinase COT1 and have been shown to have overlapping functions in various aspects of asexual development. Here, we identified two N. crassa MOB2A residues, Tyr117 and Tyr119, which are potentially phosphorylated. Using phosphomimetic mob-2a mutants we have been able to establish that apart from their previously described roles, MOB2A/B are involved in additional developmental processes. Enhanced conidial germination, accompanied by conidial agglutination, in the phosphomimetic mutants indicated that MOB2A is a negative regulator of germination. Thick-section imaging of perithecia revealed slow maturation and a lack of asci alignment in the mutant strains demonstrating a role for MOB2A in sexual development. We demonstrate that even though MOB2A and MOB2B have some overlapping functions, MOB2B cannot compensate for the roles MOB2A has in conidiation and germination. Altering Tyr residues 117 and 119 impaired the physical interactions between MOB2A and COT1, most likely contributing to some of the observed effects. As cot-1 and the phosphomimetic mutants share an extragenic suppressor (gul-1), we concluded that at least some of the effects imposed by altering Tyr117 and Tyr119 are mediated by the NDR kinase.
粗糙脉孢菌 Mps One Binder（MOB）蛋白 MOB2A 和 MOB2B 与核 Dbf2 相关（NDR）激酶 COT1 物理相互作用，并已显示在无性发育的各个方面具有重叠功能。在这里，我们鉴定了两个粗糙脉孢菌 MOB2A 残基，Tyr117 和 Tyr119，它们可能被磷酸化。使用磷酸模拟 mob-2a 突变体，我们已经能够确定，除了它们之前描述的作用外，MOB2A/B 还参与了其他发育过程。磷酸模拟突变体中增强的分生孢子萌发，伴随着分生孢子凝集，表明 MOB2A 是萌发的负调节剂。厚切片成像的产孢体显示突变菌株中成熟缓慢且缺乏减数分裂排列，表明 MOB2A 在有性发育中起作用。我们证明，尽管 MOB2A 和 MOB2B 具有一些重叠功能，但 MOB2B 不能弥补 MOB2A 在产孢和萌发中的作用。改变 Tyr 残基 117 和 119 会破坏 MOB2A 和 COT1 之间的物理相互作用，这很可能导致观察到的一些影响。由于 cot-1 和磷酸模拟突变体共享一个外显子抑制子（gul-1），我们得出结论，改变 Tyr117 和 Tyr119 所施加的至少一些影响是由 NDR 激酶介导的。
