Correia Inês, Wilson Duncan, Hube Bernhard, Pla Jesús
iBiMED-Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Agra do Crasto, 3810-193 Aveiro, Portugal.
Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Exeter EX4 4QD, UK.
J Fungi (Basel). 2020 Oct 17;6(4):230. doi: 10.3390/jof6040230.
The success of as a pathogen relies on its ability to adapt and proliferate in different environmental niches. Pathways regulated by mitogen-activated protein kinases (MAPKs) are involved in sensing environmental conditions and developing an accurate adaptive response. Given the frequent cooperative roles of these routes in cellular functions, we have generated mutants defective in all combinations of the four described MAPKs in and characterized its phenotype regarding sensitiveness to specific drugs, morphogenesis and interaction with host immune cells. We demonstrate that all MAPKs are dispensable in this yeast as a mutant defective in Cek1, Cek2, Mkc1 and Hog1 is viable although highly sensitive to oxidative and osmotic stress, displaying a specific pattern of sensitivity to antifungals. By comparing its phenotype with single, double and triple combinations of MAPK-deletion mutants we were able to unveil a Cek1-independent mechanism for Hog1 resistance to Congo red, and confirm the predominant effect of Hog1 on oxidative and osmotic adaptation. The quadruple mutant produces filaments under non-inducing conditions, but is unable to develop chlamydospores. Furthermore, cells switch to the opaque state at high frequency, which is blocked by the ectopic expression of suggesting a role of this kinase for phenotypic switching.
作为一种病原体，其成功依赖于它在不同环境生态位中适应和增殖的能力。丝裂原活化蛋白激酶（MAPK）调控的信号通路参与感知环境条件并产生精确的适应性反应。鉴于这些信号通路在细胞功能中频繁发挥协同作用，我们构建了该菌中上述四种MAPK所有组合缺陷的突变体，并对其在对特定药物的敏感性、形态发生以及与宿主免疫细胞相互作用方面的表型进行了表征。我们证明，在这种酵母中所有MAPK都是非必需的，因为Cek1、Cek2、Mkc1和Hog1均缺陷的突变体虽然对氧化应激和渗透应激高度敏感，但仍可存活，且呈现出对抗真菌药物的特定敏感性模式。通过将其表型与MAPK缺失突变体的单重、双重和三重组合进行比较，我们发现了一种不依赖Cek1的Hog1对刚果红耐药的机制，并证实了Hog1在氧化应激和渗透应激适应中的主要作用。四重突变体在非诱导条件下产生菌丝，但无法形成厚垣孢子。此外，该菌细胞在高频下转变为不透明状态，而异位表达可阻断这种转变，这表明该激酶在表型转换中发挥作用。
