Post-translational Modifications (PTMs): Deciphering the PTM codes of proteins and uncovering their potential as therapeutic targets and molecular switches for regulating protein functions in health and disease.

During the past six years our group has made remarkable progress towards deciphering the post-translational modification (PTM) code of several proteins that play central roles in the pathogenesis of neurodegenerative diseases such as Parkinson’s disease, Huntington’s disease and Alzheimer’s disease. In addition to developing novel protein synthesis strategies that enable site-specific introduction of signle or multiple PTMs, we have also contributed to the development of novel methodologies that enabled for the first time site-specific nitration of proteins. These advances have enabled us, for the first time, to generate libraries of homogenously modified proteins that reproduce the proteome diversity observed for these proteins under physiologic and pathologic conditions. For example, we have generated a library of 32 homogeneously modified alpha-synuclein proteins that includes all α-syn spilicing forms, disease-linked mutations and post-translationally modified forms that have been detected in human brain, CSF and plasma. Similarly, we have successfully prepared more than 50 homogeneously modified form of exon1 of the Huntingtin protein, bearing single or multiple PTMs within the N-terminal 17 amino acids. In addition to enabling novel insight into the role of PTMs in regulating protein function in health and disease, these advances will enable us for the first time to develop novel and robust tools and methodologies to decipher the PTM codes of proteins and to uncover their true potential as therapeutic targets and molecular switches for regulating protein functions in health, disease and therapeutics.

Research Priorities
  • Develop novel synthetic and semisynthetic strategies that enable site-specific post-translational modifications of Tau and TDp-43 and full-length Huntingtin.
  • Develop novel tools and methodologies to investigate the role of PTMs in regulating protein structure and function with spatial and temporal resolution with special emphasis on disease-associated PTMs and PTMs that remain inaccessible to the research community today.
  • Developing and applying novel tools and methodologies to investigate the interplay between PTMs and to decipher novel complex regulator mechanisms that are regulated by the crosstalk between different PTMs.
  • In collaboration with bioinformatics and structural biology groups, we plan to leverage the experimental structural, biophysical and cellular data generated using our comprehensive libraries of site-specifically modified proteins to develop novel computational tools to 1) predict the effect of specific PTMs on protein structure and aggregation; 2) decipher the roles governing cross-talk between different and competing PTMs; 3) determine the general rules of when natural mutations can be used to mimic post-translational mutations when investigating biological and/or disease mechanisms and pathways in cells and in vivo.
  • Discovery of novel enzymes and regulatory networks that regulate the levels of proteins linked to neurodegenerative disease through modulation of their PTMs.