Conformational Dynamics of Pin1 Regulation of APP processing and Abeta Production
EMSL Project ID
17802
Abstract
The proposed studies fall within the EMSL science theme of "Biological Interactions and Interfaces". The experiments that we propose build on extensive literature that indicates that aberrant regulation of APP processing and Abeta production is a major cause of Alzheimer?s disease, and that phosphorylation of the APP intracellular domain (AICD) at residue T668 plays an important role in this process. Our previous work showed that the phosphorylated pThr668Pro motif in this domain is in equilibrium between distinct cis and trans conformations of the prolyl peptide bond (Ramelot, Gentile et al. 2000; Ramelot and Nicholson 2001). Our recent work shows that cis/trans isomerization of the APP pThr668Pro motif is greatly accelerated by Pin1-catalyzed prolyl isomerization and that Pin1 promotes non-amyloidogenic APP processing and reduces Abeta production (Pastorino et al., in press). These results suggest that the cis conformation of the pThr668-Pro motif facilitates entry of APP into an amyloidogenic processing pathway, and Pin1-catalyzed cis/trans isomerization of the pT668P motif kinetically decouples the cis isomer from the amyloidogenic pathway thereby providing protection from amyloidogenesis. We propose a set of NMR experiments that will allow us to investigate this novel hypothesis. We propose to determine the fundamental biophysical mechanisms by which Pin1 regulates pT668-APP conformation, with a focus on elucidating functional motions in Pin1. These experiments will extend our limited structure-based understanding of Pin1 function, taking it to a new level in which function is explored not by simply examining the proximity and chemistry of atoms within enzyme:substrate or enzyme:inhibitor complexes, but rather by determining correlations between the rates associated with individual steps of the reaction pathway and the rates of backbone motion within the enzyme to elucidate functional motions and to identify critical residues that participate in these motions. This proposal enters unexplored territory in the area of APP processing and A production, and the anticipated outcomes of the proposed work have tremendous potential for the development of new drugs for the prevention and/or treatment of AD.Pastorino, L., Sun, A., Lu, P.-J., Zhou, X. Z., Balastik, M., Finn, G., Wulf, G., Lim, J., Li, S.-H., Li, X., Xia, W., Nicholson, L. K. and Lu, K. P. (2006) The prolyl isomerase Pin1 regulates amyloid precursor protein processing and Abeta production. Nature, in press.
Ramelot, T. A., L. N. Gentile, et al. (2000). "Transient structure of the amyloid precursor protein cytoplasmic tail indicates preordering of structure for binding to cytosolic factors." Biochemistry 39(10): 2714-25.
Ramelot, T. A. and L. K. Nicholson (2001). "Phosphorylation-induced structural changes in the amyloid precursor protein cytoplasmic tail detected by NMR." J Mol Biol 307(3): 871-84.
Project Details
Project type
Capability Research
Start Date
2006-05-09
End Date
2007-05-21
Status
Closed
Released Data Link
Team
Principal Investigator