Abstract
Cadmium is a carcinogen that can induce ER stress, DNA damage, oxidative stress and cell death. The yeast mitogen-activated protein kinase (MAPK) signalling pathways paly crucial roles in response to various stresses. Here, we demonstrate that the unfolded protein response (UPR) pathway, the high osmolarity glycerol (HOG) pathway and the cell wall integrity (CWI) pathway are all essential for yeast cells to defend against the cadmium-induced toxicity, including the elevated ROS and cell death levels induced by cadmium. We show that the UPR pathway is required for the cadmium-induced phosphorylation of HOG_MAPK Hog1 but not for CWI_MAPK Slt2, while Slt2 but not Hog1 is required for the activation of the UPR pathway through the transcription factors of Swi6 and Rlm1. Moreover, deletion of HAC1 and IRE1 could promote the nuclear accumulation of Hog1, and increase the cytosolic and bud neck localisation of Slt2, indicating crucial roles of Hog1 and Slt2 in regulating the cellular process in the absence of UPR pathway. Altogether, our findings highlight the significance of these two MAPK pathways of HOG and CWI and their interrelationship with the UPR pathway in responding to cadmium-induced toxicity in budding yeast.
Highlights
Cadmium (Cd) is a toxic heavy metal that can induce oxidative stress, cell death, DNA damage and even cancer in humans [1,2]
These results indicate that the components of the high osmolarity glycerol (HOG) pathway are essential for Cd tolerance and the Ire1 and Hac1-mediated unfolded protein response (UPR) pathway contributes to the phosphorylation activation of spliced normally as that of WT cells in response to Cd or TM stress (Figure 1C)
HOG pathway participates in hyper-osmotic stress response and the ER stress response [30,48], while the CWI pathway is involved in cell wall integrity stress, ER stress, hypo-osmotic stress response, and inheritance regulation [35,36,37]
Summary
Cadmium (Cd) is a toxic heavy metal that can induce oxidative stress, cell death (apoptosis), DNA damage and even cancer in humans [1,2]. Increased intracellular ROS levels can cause endoplasmic reticulum stress (ER stress), cell death (apoptosis) and DNA damage [6,7]. The cadmium-induced cell death needs the caspase Yca and is dependent on glucose [8]. Cd-induced cell death is mediated by the calcium signalling pathway [9]. Cd lead to a rapid elevation of the cytosolic calcium and the perturbation of ER calcium homeostasis can cause ER stress and, induce cell death [10,11]
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