Role of Misfolded Proteins in the Pathogenesis of Neurodegenerative Disorders and Challenges impacting the development of Novel Therapies. An Overview. A hallmark of neurodegenerative proteinopathies is the formation of misfolded protein aggregates that cause cellular toxicity and contribute to cellular proteostatic collapse. Therapeutic targeting of protein misfolding has generated unique challenges for drug discovery and development for several reasons, including: 1)The dynamic nature of the protein species involved, 2)Uncertainty about which forms of a given disease protein such as Monomers, Oligomers, or Insoluble aggregates, are primarily responsible for cellular toxicity, 3)Our still limited understanding about which components of the cellular proteo-static machinery these disease proteins interact with and 4) Lack of well-validated biomarkers for clinical trials. Therapeutic options are currently being explored that target different steps in the production and processing of proteins implicated in neurodegenerative disease, including synthesis, chaperone-assisted folding and trafficking, and degradation via the proteasome and autophagy pathways. Other therapies, like mTOR inhibitors and activators of the heat shock response, can rebalance the entire proteostatic network. Hence an attempt has been made in this E-Booklet to discuss major challenges that impact the development of novel therapies, including incomplete knowledge of druggable disease targets and their mechanism of action as well as a lack of biomarkers to monitor disease progression and therapeutic response. …Dr. H. K. Saboowala. M.B.(Bom) .M.R.S.H.(London)