The polysaccharide chains of heparan sulfate proteoglycan (HSPG) may undergo marked variation in the relative amounts of N-acetylated and N-sulfated glucosamine (G1cN) residues, the relative amounts of D-glucuronic and L-iduronic acid residues, and the degree of sulfation. These polymers, found in all cells examined to date, are synthesized, secreted, endocytosed and catabolized rapidly in cultured hepatocytes and other cells; yet, their physiological role is unknown. Our long term objective is to determine the role(s) played by these structurally variable and rapidly turned over polymers. To these ends, the specific aims for the immediate future are to describe the metabolism of HSPG in a cultured hepatocyte cell line with particular emphasis on the intracellular routing of HSPG during synthesis, secretion, and endocytosis and the structural changes in HSPG as it passes from one organelle to another. Particular emphasis will be placed on the structural features of the heparan sulfate (HS) chains at different stages of HSPG metabolism. The structural analyses will involve HPLC profiling of the oligosaccharide fragments formed by nitrous acid cleavage of HS chains either at the N-sulfated G1cN residues, or at the N-acetylated G1cN residues after hydrazinolysis of the polymers. Several of the profiling procedures will be developed during the course of these studies and will be extensions of a previous profiling procedure developed for determining the structure for heparan.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL021763-18
Application #
3336605
Study Section
Pathobiochemistry Study Section (PBC)
Project Start
1978-02-01
Project End
1988-01-31
Budget Start
1987-02-01
Budget End
1988-01-31
Support Year
18
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Illinois Urbana-Champaign
Department
Type
Schools of Arts and Sciences
DUNS #
041544081
City
Champaign
State
IL
Country
United States
Zip Code
61820
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Fedarko, N S; Ishihara, M; Conrad, H E (1989) Control of cell division in hepatoma cells by exogenous heparan sulfate proteoglycan. J Cell Physiol 139:287-94
Guo, Y C; Conrad, H E (1988) Analysis of oligosaccharides from heparin by reversed-phase ion-pairing high-performance liquid chromatography. Anal Biochem 168:54-62
Ishihara, M; Fedarko, N S; Conrad, H E (1987) Involvement of phosphatidylinositol and insulin in the coordinate regulation of proteoheparan sulfate metabolism and hepatocyte growth. J Biol Chem 262:4708-16
Ishihara, M; Fedarko, N S; Conrad, H E (1986) Transport of heparan sulfate into the nuclei of hepatocytes. J Biol Chem 261:13575-80
Fedarko, N S; Conrad, H E (1986) A unique heparan sulfate in the nuclei of hepatocytes: structural changes with the growth state of the cells. J Cell Biol 102:587-99
Bienkowski, M J; Conrad, H E (1985) Structural characterization of the oligosaccharides formed by depolymerization of heparin with nitrous acid. J Biol Chem 260:356-65
Bienkowski, M J; Conrad, H E (1985) Oligosaccharides formed by treatment of heparin with nitrous acid. Semin Thromb Hemost 11:86-8