Graduation Year
2016
Document Type
Dissertation
Degree
Ph.D.
Degree Name
Doctor of Philosophy (Ph.D.)
Degree Granting Department
Medical Sciences
Major Professor
Robert Deschenes, Ph.D.
Co-Major Professor
Vladimir Uversky, Ph.D., D.Sc.
Committee Member
Yu Chen, Ph.D.
Committee Member
Gloria Ferreira, Ph.D.
Committee Member
Sameer Varma, Ph.D.
Committee Member
Walter Schmidt, Ph.D.
Keywords
Acylation, Protein Acyltransferase, Intrinsically Disordered Protein, Fatty Acid Metabolism, Palmitoylation Predictor, X-Linked Intellectual Disability
Abstract
Protein palmitoylation refers to the process of adding a 16-carbon saturated fatty acid to the cysteine of a substrate protein, and this can in turn affect the substrate’s localization, stability, folding, and several other processes. This process is catalyzed by a family of 23 mammalian protein acyltransferases (PATs), a family of transmembrane enzymes that modify an estimated 10% of the proteome. At this point in time, no structure of a protein in this family has been solved, and therefore there is poor understanding about the regulation of the enzymes and their substrates. Most proteins, including palmitoylation enzymes and substrates, have some level of intrinsic disorder, and this flexibility can be important for signaling processes such as protein- protein interactions and post-translational modifications. Therefore, we assumed that examining intrinsic disorder in palmitoylation enzymes and substrates would yield insight into their regulatory mechanisms. First, we found that among other factors, utilizing intrinsic disorder predictions led to a palmitoylation predictor that significantly outperformed existing predictors. Next, we discovered a conserved region of predicted disorder-to-order transition in the disordered C-termini of the PAT family. In Erf2, the yeast Ras PAT, we developed a model where this region reversibly interacts with membranes, and we found that this region mediates interaction with Acc1, an enzyme involved in fatty acid metabolism processes. Finally, we found that an XLID-associated nonsense mutation in zDHHC9, the mammalian Ras PAT, removed a disordered region that was critical for enzyme localization. Future studies of palmitoylation utilizing the framework of intrinsic disorder may lead to additional insights about this important regulatory process.
Scholar Commons Citation
Reddy, Krishna D., "Regulation of Palmitoylation Enzymes and Substrates by Intrinsically Disordered Regions" (2016). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/6572
