Cellular Mechanisms to Respond to Cadmium Exposure: Ubiquitin Ligases

Cadmium is increasingly used in industrial processes and is therefore becoming a mounting threat to the environment and human health. Ubiquitination has emerged as an important regulation mechanism in many processes, so it is no surprise that this protein modification plays a central role in the cellular response to cadmium exposure. The key enzymes in the process of ubiquitination are the E3 ubiquitin ligases due to their ability to confer substrate specificity. We present an overview of the roles of three such E3 ubiquitin ligases during cadmium stress in yeast and human cells. We discuss substrates and regulatory mechanisms of budding yeast SCFMet30, fission yeast SCFPof1, and the mammalian Cul3/Keap1 ligase. The similarities and differences of these ubiquitin ligases that coordinate the cadmium stress response in yeast and human will be highlighted to describe the different mechanisms for cadmium sensing and detoxification.