Fu, Janine

Janine is in the Biochemistry, Molecular and Structural Biology Graduate Program, and joined the CMB training program in 2018.  She received a B.S. degree in Biochemistry from UCLA.

Mentor: Dr. Joseph Loo

Research project:

            Post-translational modification of proteins is a conserved strategy used by organisms to efficiently control biological mechanisms, allowing rapid adaptive cellular responses.  In eukaryotes, the physiological relevance of lysine protein acetylation has been well characterized and associated with diverse functions such as histone modification and metabolic regulation. In prokaryotes, however, few proteins were known to be acetylated until the past decade when characterization of acetylation in microbial proteins increased due to the development of high throughput proteomic techniques. Most acetylated microbial proteins are metabolic enzymes such as acetyl-CoA synthetase and the extent of acetylation has been shown to correlate with metabolic changes in response to nutrient availability.  Lysine modifications extend beyond acetylation, which can include a wide range of recently discovered acylations.  Previous work in the Loo lab found that the obligate syntrophs, Syntrophomonas wolfei and Syntrophic aciditrophicus, accumulate a variety of novel acyl modifications, such as butyrylation and crotonylation, from substrate degradation of fatty acids and aromatics.

            My research aims to identify and characterize acyl-lysine modifications in photosynthetic α-proteobacterium Rhodopseudomonas palustris using quantitative mass spectrometric methods.  Although previous literature identified lysine acetylation sites in acyl-CoA synthetases in R.palustris, little is known about its other acyl modifications.  The organism’s ability to switch between four distinct metabolic modes highly suggest that the acyl-CoA produced during substrate degradation could lead to other acyl-lysine modifications.  By quantifying acylation levels under different cultivation conditions, we can elucidate how these modifications optimize the microbe’s complex metabolic system.  Through this work, I will gain insight into the relationship between protein acylation, nutrient sensing, and metabolic homeostasis, a global process spanning from bacteria to mammals.