This week I am due to host a journal club. A ritual which gives me great opportunity to make others feign interest in something that I am excited about. This time around I have chosen to force them to read about a protein I have been interested in for some time called ‘p21’. The paper I chose was recently published in the Journal of Biological Chemistry and for your info is titled ‘Reactive Oxygen Species and Mitochondrial Sensitivity to Oxidative Stress Determine Induction of Cancer Cell Death by p21’. As exciting as this sounds, it may be easier to ignore the title, and I’ll try and explain a little bit about it.
Proteins such as p21 fit into what we like to call cell signalling pathways. These pathways exist within single cells and act as a courier service for messages to be passed from one part of the cell to another. This is much in the same way that your brain receives signals from the nervous system and sends signals back out to elicit a response. Biologists have constructed these networks (made up of proteins) as a way of mapping how a message can be sent from the cell membrane to the nucleus and tell your DNA to express certain genes.
p21 is a very interesting protein because the gene that makes p21 is controlled by a very important protein called p53. This protein is sometimes called the ‘guardian of the genome’ due to its role in protecting the cell from becoming cancerous. Its job is to make sure that cell division and cell growth occur correctly and also acts as a suicide switch should the cell become damaged in a way that could lead to the formation of cancer. Scientists have found that the gene producing p53 is mutated in over 50% of cancers. The result of this is a cell may produce no p53 or produces a form of p53 which doesn’t function properly. No more control of cell growth and no more preventing damaged cells from multiplying.
It has been known for some time that proteins such as p53 and p21 are involved in a wide range of messenger networks and are responsible for many diverse cellular functions. What is now emerging is a better understanding of what makes these proteins do one thing and not another. The paper above demonstrates some of that recent research and highlights how further understanding of how these proteins operate will lead to better treatments for cancer.
