Research Interests
My research explores mechanisms used by living cells to control the synthesis and degradation of protein. Specifically, we use of mass spectrometry and stable isotopes to label newly synthesized molecules with a time dependent tag. This allows us to measure both in vivo concentrations, and replacement rates. With a mass spectrometer, the time-dependent stable isotope enrichment can be measured in any molecule of a complex mixture. This allows us to monitor large numbers of proteins simultaneously and perform experiments that survey broad sections of the proteome. We have successfully used this technique in many different biosynthetic systems from "cell free" environments to humans (see Figure).Currently, we are focused on understanding post-transcriptional control of the proteome composition within cells, using stored mRNA and protein degradation
Post-transcriptional control of cell metabolism using stored mRNA. Multiple processes critical to human health are known to employ stored mRNA, yet these systems are difficult to investigate using current tools. The mRNA is present in the cell for an indefinite period of time before signal dependent translation of the specific protein occurs. By following signal specific protein synthesis we can approach the understanding of these systems from the 'bottom up' to identify the biochemical pathways activated within the cell.
Maintenance of proteome homeostasis through protein catabolism. Many of the today’s most devastating diseases, can be identified as diseases of protein homeostasis. Parkinson’s, Alzheimer’s, Huntington’s, diabetes and other diseases all exhibit cellular deposits of aggregated protein. These aggregates are often highly resistant to degradation and may indicate a dysfunction within the catabolic machinery of the cell. Continuous protein catabolism is critical in the presence of constitutive translation and transcription, yet these processes are poorly understood. It has recently been shown that the cell employs thousands of proteins, (ubiquitin ligases, targeted proteases, proteasome, etc.) to guide the process of protein degradation. Thus, the complexity of the regulatory structure for removing a protein from the cell may be comparable to that used in synthesizing the protein. Our current work is focused on identifying the substrates for proteolytic processes (autophagy and cellular proteases) then understanding how targeted proteolytic processing is used by the cell.
Teaching Interests
Teaching biochemistry and the techniques for independent research as well as the how to monitor in vivo synthesis and catabolismProfessional Citizenship
- Reviewer, Ad Hoc Reviewer, Aging Cell (2014 - Present)