Diverse cellular responses to oxidative stress

This past week, everyone had the opportunity to present their project to the other BSURFers through a chalk talk.

I found Julia’s talk particularly interesting, as her work on Oxidative Stress relates to what I am working on in the Pendergast Lab. Reactive Oxygen Species (ROS) cause cellular damage. By oxidizing amino acid residues, ROS can alter protein structure, causing protein unfolding, aggregation and plaque formation. There are two general mechanism by which the cell responds to such damage: damaged proteins are either degraded or repaired. Julia’s project focuses on a process called ubiquitination. It is the cell’s method of flagging damaged proteins for degradation. K48 ubiquitins are secondary ubiquitin molecules that are attached to the primary ubiquitin’s position 48 lysine (K48) residue. K48 ubiquitination is not understood as well as other forms of ubiquitination. Julia’s project focuses on identifying which enzymes flag proteins with specifically K48 ubiquitins. She is also interested in whether K48 accumulation on proteins following oxidative stress is the result of reduced proteasome activity, or reduced deubiquinating activity.

My project looks at ROS from a somewhat different angle. I focus on system xCT, which is a membrane antiporter responsible for importing cystine into the cytoplasm. Cystine is an important starting molecule in an oxidative stress response pathway. Through a number of intermediates, cystine is converted to glutathione, which quenches harmful reactive oxygen species through conversion to glutathione disulfide. While my project looks at how cells quench ROS before they can damage cellular components, Julia’s project focuses on how cells deal with proteins that have been damaged. It was nice to discover a connection between my project and that of another BSURFer, and I would be interested to see whether anyone in Julia’s lab studies the glutathione synthesis pathway.

Leave a Reply

Your email address will not be published. Required fields are marked *