Lysosome function is essential for the normal development and good health of humans and other higher organisms. Patients with deficiencies in individual or multiple lysosomal enzymes exhibit acute and chronic health problems including mental retardation, developmental deformities, cardiac impairment, and premature death. In addition, alterations in lysosomal enzyme targeting may have important consequences in a number of widespread human illnesses including cancer and Alzheimer disease. Most lysosomal enzymes are delivered to the lysosome by the mannose 6-phosphate (M6P) dependent targeting system. In this pathway, lysosomal enzymes are phosphorylated on selected mannose residues and then bind to two M6P receptors (MPRs), the large, cation-independent M6P/IGF2 receptor and the small, cation-dependent M6P receptor. The MPRs function in concert to deliver the enzymes to lysosomes. The overall objective is to determine the relative roles of the two M6P receptors in the targeting of lysosomal proteins to the lysosome. Mutant mice and cell lines defective in one or both receptor will be evaluated for changes in lysosomal targeting. Experiments will include determining the affinity of the two receptors for enzymes bearing M6P residues and determining the subcellular distribution of the proteins and receptors. Second, structure function studies will be done on the M6P/IGF2 receptor to determine functional domains and to identify other receptor-binding proteins that may be involved in trafficking.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK045992-06
Application #
2668307
Study Section
Medical Biochemistry Study Section (MEDB)
Program Officer
Mckeon, Catherine T
Project Start
1993-03-01
Project End
2001-02-28
Budget Start
1998-03-01
Budget End
1999-02-28
Support Year
6
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Medicine & Dentistry of NJ
Department
Miscellaneous
Type
Schools of Medicine
DUNS #
622146454
City
Piscataway
State
NJ
Country
United States
Zip Code
08854
Tyynela, J; Sohar, I; Sleat, D E et al. (2001) Congenital ovine neuronal ceroid lipofuscinosis--a cathepsin D deficiency with increased levels of the inactive enzyme. Eur J Paediatr Neurol 5 Suppl A:43-5
Lin, L; Sohar, I; Lackland, H et al. (2001) The human CLN2 protein/tripeptidyl-peptidase I is a serine protease that autoactivates at acidic pH. J Biol Chem 276:2249-55
Sohar, I; Lin, L; Lobel, P (2000) Enzyme-based diagnosis of classical late infantile neuronal ceroid lipofuscinosis: comparison of tripeptidyl peptidase I and pepstatin-insensitive protease assays. Clin Chem 46:1005-8
Tyynela, J; Sohar, I; Sleat, D E et al. (2000) A mutation in the ovine cathepsin D gene causes a congenital lysosomal storage disease with profound neurodegeneration. EMBO J 19:2786-92
Naureckiene, S; Sleat, D E; Lackland, H et al. (2000) Identification of HE1 as the second gene of Niemann-Pick C disease. Science 290:2298-301
Sohar, I; Sleat, D E; Jadot, M et al. (1999) Biochemical characterization of a lysosomal protease deficient in classical late infantile neuronal ceroid lipofuscinosis (LINCL) and development of an enzyme-based assay for diagnosis and exclusion of LINCL in human specimens and animal models. J Neurochem 73:700-11
Sleat, D E; Gin, R M; Sohar, I et al. (1999) Mutational analysis of the defective protease in classic late-infantile neuronal ceroid lipofuscinosis, a neurodegenerative lysosomal storage disorder. Am J Hum Genet 64:1511-23
Jadot, M; Lin, L; Sleat, D E et al. (1999) Subcellular localization of mannose 6-phosphate glycoproteins in rat brain. J Biol Chem 274:21104-13
Liu, C G; Sleat, D E; Donnelly, R J et al. (1998) Structural organization and sequence of CLN2, the defective gene in classical late infantile neuronal ceroid lipofuscinosis. Genomics 50:206-12
Sleat, D E; Sohar, I; Pullarkat, P S et al. (1998) Specific alterations in levels of mannose 6-phosphorylated glycoproteins in different neuronal ceroid lipofuscinoses. Biochem J 334 ( Pt 3):547-51

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