Research proposed in this application seeks to continue the applicant's genetic and molecular studies on Presenilin function and its role in the intracellular trafficking and proteolytic processing of its substrate proteins. Mutant human Presenilins influence the proteolysis of amyloid precursor protein (APP), resulting in an accelerated accumulation of the neurotoxic amyloid peptides during Alzheimer's disease. In the model organisms Caenorhabditis and Drosophila, Presenilins are required for Notch/Lin-12 developmental signaling. Presenilins have recently been shown to regulate proteolytic processing events during Notch receptor maturation and signaling that may be analogous to the Presenilin-dependent cleavages of APP in Alzheimer's disease. Finally, Presenilins have also been implicated in the cellular response to apoptotic stimuli in both mammalian cells and Drosophila. Mosaic tissue studies will be performed in vivo using newly isolated Presenilin gene mutants. Preliminary experiments have revealed integrin-like phenotypes in the mutant tissue clones, prompting the applicants to analyze the role of Presenilin in integrin cleavage using the genetic and biochemical approaches that have been used previously to demonstrate the effects of Presenilin on Notch processing. These studies may reveal shared feature of Presenilin substrates and lead to a better understanding of the specific pathway of protein processing controlled by Presenilin. A central goal of this proposal is to develop an extensive collection of new molecular probes to dissect Notch processing at much higher resolution than is currently possible. These reagents, including new antibodies and epitope-tagged constructs that can discriminate among Notch cleavage products, will be combined with mutational and proteolysis inhibition studies to identify the biochemical steps of Notch processing that involve Presenilin. Genetic and molecular screens for Presenilin-interacting factors will also be performed, taking advantage of the applicant's recent finding that the conserved C-terminus of Presenilin is a crucial functional domain. Finally, detailed parallel studies on the trafficking of Notch and other proteins will be undertaken in tissues lacking either Presenilin or another protein with known effect of subcellular trafficking, the SERCA-type Calcium-ATPase. These experiments are made possible by the applicant's recent isolation of Calcium-ATPase mutants, and they will address the unresolved issue of whether Presenilin is required for protein trafficking or only proteolysis. The studies proposed here will clarify the biochemical activity of Presenilin in the processing of Notch, APP and other proteins, and may ultimately increase our understanding of the molecular causes of Alzheimer's disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
2R01AG014583-04
Application #
6124218
Study Section
Special Emphasis Panel (ZRG1-MDCN-2 (01))
Program Officer
Snyder, D Stephen
Project Start
1997-05-01
Project End
2005-04-30
Budget Start
2000-07-01
Budget End
2001-04-30
Support Year
4
Fiscal Year
2000
Total Cost
$313,783
Indirect Cost
Name
University of Pennsylvania
Department
Genetics
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
McBride, Sean M J; Choi, Catherine H; Schoenfeld, Brian P et al. (2010) Pharmacological and genetic reversal of age-dependent cognitive deficits attributable to decreased presenilin function. J Neurosci 30:9510-22
Lu, Yisheng; Lv, Yubing; Ye, Yihong et al. (2007) A role for presenilin in post-stress regulation: effects of presenilin mutations on Ca2+ currents in Drosophila. FASEB J 21:2368-78
Seidner, Glen A; Ye, Yihong; Faraday, Martha M et al. (2006) Modeling clinically heterogeneous presenilin mutations with transgenic Drosophila. Curr Biol 16:1026-33
Periz, Goran; Fortini, Mark E (2004) Functional reconstitution of gamma-secretase through coordinated expression of presenilin, nicastrin, Aph-1, and Pen-2. J Neurosci Res 77:309-22
Hu, Yue; Fortini, Mark E (2003) Different cofactor activities in gamma-secretase assembly: evidence for a nicastrin-Aph-1 subcomplex. J Cell Biol 161:685-90
Heidary, G; Fortini, M E (2001) Identification and characterization of the Drosophila tau homolog. Mech Dev 108:171-8
Fortini, M E; Skupski, M P; Boguski, M S et al. (2000) A survey of human disease gene counterparts in the Drosophila genome. J Cell Biol 150:F23-30
Ye, Y; Fortini, M E (2000) Proteolysis and developmental signal transduction. Semin Cell Dev Biol 11:211-21
Ye, Y; Fortini, M E (1999) Apoptotic activities of wild-type and Alzheimer's disease-related mutant presenilins in Drosophila melanogaster. J Cell Biol 146:1351-64
Lukinova, N I; Roussakova, V V; Fortini, M E (1999) Genetic characterization of cytological region 77A-D harboring the presenilin gene of Drosophila melanogaster. Genetics 153:1789-97

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