The pheromone response and the high osmolarity glycerol (HOG) pathways are considered the prototypical MAPK signaling systems. They are the best-understood pathways in eukaryotic cells, yet they continue to provide insights in how cells relate with the environment. These systems are subjected to tight regulatory circuits to prevent hyperactivation in length and intensity. Failure to do this may be a matter of life or death specially for unicellular organisms such as Saccharomyces cerevisiae. The signaling pathways are fine-tuned by positive and negative feedback loops exerted by pivotal control elements that allow precise responses to specific stimuli, despite the fact that some elements of the systems are common to different signaling pathways. Here we describe the experimentally proven negative feedback loops that modulate the pheromone response and the HOG pathways. As described in this review, MAP kinases are central mechanistic components of these feedback loops. They have the capacity to modulate basal signaling activity, a fast extranuclear response, and a longer-lasting transcriptional process.

信息素反应和高渗透压甘油（HOG）途径被认为是典型的MAPK信号传导系统。它们是真核细胞中最容易理解的途径，但它们仍在继续提供有关细胞与环境之间关系的见解。这些系统经过严格的调节电路，以防止长度和强度过度激活。未能做到这一点可能是生死攸关的问题，特别是对于酿酒酵母等单细胞生物而言。尽管系统的某些元件是不同信号通路所共有的事实，但是通过枢轴控制元件施加的正反馈和负反馈回路可以对信号通路进行微调，这些枢轴控制元件允许对特定刺激做出精确响应。在这里，我们描述了实验证明的负反馈回路，可调节信息素反应和HOG途径。如本综述所述，MAP激酶是这些反馈回路的中心机制。它们具有调节基础信号转导活性，快速的核外反应和更长的转录过程的能力。