Characterizing the Contributions of Individual Components to the Dynamic Properties of the HOG Pathway in S. Cerevisiae

Abstract

Cellular pathways function through time-dependent interactions between numerous components. These signaling dynamics determine the speed at which interactions occur and set signal processing behavior. To understand the mechanisms governing the signal processing in a signaling pathway, we need to understand its dynamics and how each of the different parts of the pathway set the dynamics. In this study, we used the high osmolarity glycerol (HOG) pathway in yeast as a model pathway to examine the effect various components of signaling pathways have on signaling dynamics. Specifically, we investigated how individual components of the HOG pathway affect signaling dynamics by analyzing the impact of deletions of specific components on the ability of the pathway to respond to a range of osmotic stimuli. We developed a hyper-osmotic step shock assay and used it to screen a library of deletion mutants for specific mutants displaying altered dynamic responses.

Next, we examined the effects of specific deletions on the frequency dependent responses of the HOG pathway in order to further explore their roles in setting the dynamics of HOG signaling. Our results indicated that the deletion of PTP3 or GPD1 decreased the HOG pathway's response to repeated hyper-osmotic shocks across a wide range of frequencies. Additionally, we found that the deletion of FPS1 resulted in the termination of the HOG pathway's ability to respond to repeated hyper-osmotic shocks. Together, these results demonstrate some previously uncharacterized effects of the deletion of components of the HOG pathway on its signaling dynamics.