Department of Computational Biology, Center for Computational Biology, IIIT-Delhi, India.
FEBS Open Bio. 2022 Oct;12(10):1700-1716. doi: 10.1002/2211-5463.13470. Epub 2022 Aug 30.
Recent biochemical experiments have indicated that in Candida albicans, a commensal fungal pathogen, the Ras signaling pathway plays a significant role in the yeast-to-hyphal transition; specifically, two enzymes in this pathway, Adenyl Cyclase Cyr1 and GTPase activating protein Ira2, facilitate this transition, in the presence of energy sensor ATP. However, the precise mechanism by which protein interactions between Ira2 and Cyr1 and the energy sensor ATP result in the yeast-to-hyphal transition and create a switch-like process are unknown. We propose a new set of biochemical reaction steps that captures all the essential interactions between Ira2, Cyr1, and ATP in the Ras pathway. With the help of chemical reaction network theory, we demonstrate that this set of biochemical reaction steps results in bistability. Further, bifurcation analysis of the differential equations based on this set of reaction steps supports the existence of a bistable switch, and this switch may act as a checkpoint mechanism for the promotion of growth-to-hyphal transition in C. albicans.
最近的生化实验表明,在白色念珠菌(一种共生真菌病原体)中,Ras 信号通路在酵母到菌丝的转变中起着重要作用;具体来说,该通路中的两种酶,腺苷酸环化酶 Cyr1 和 GTP 酶激活蛋白 Ira2,在能量传感器 ATP 的存在下促进了这种转变。然而,Ira2 和 Cyr1 与能量传感器 ATP 之间的蛋白质相互作用如何导致酵母到菌丝的转变并产生类开关过程尚不清楚。我们提出了一组新的生化反应步骤,这些步骤捕获了 Ras 通路中 Ira2、Cyr1 和 ATP 之间的所有必要相互作用。借助化学反应网络理论,我们证明了这组生化反应步骤导致了双稳性。此外,基于该组反应步骤的微分方程的分岔分析支持存在双稳态开关,该开关可能作为促进 C. albicans 生长到菌丝转变的检查点机制。