Abstract

The group of proteins which activate three sphingolipid hydrolases (glucocerebrosidase, galatocerebrosidase, and sphingomyelinase) will be studied in depth. We will develop an immunoassay for measuring their concentration in different brain cell types and subcellular fractions, organs, and fluids. Changes in these concentrations as a function of age and physiological state, including genetic disorders of sphingolipid metabolism, will be measured in an effort to elucidate their functions. The antibodies will also be used to prepare and immunoaffinity column as an aid in the large-scale isolationof the activators. Chemical studies will be made with the activaters to determine their amino acid sequences and to identify the regions needed for activating the enzymes. It may be possible to use the activators as stabilizers of the enzymes in order to improve the effeciveness of enzyme therapy of the disorders (especially Gaucher disease). Similar studies will be made of the proteins which aid in the transfer of cerebrosides between membranes. We will try to prepare active degradation products of the proteins and also see if the proteins stimulate the action of various glycopid synthetases. Further study of the changes in brain sphingolipids that are produced by fasting will be done. We will investigate the possibility that the level of free fatty acids in brain controls the level of ceramide. Enzyme studies will be carried out in brain membrane fractions to see if there are indeed five enzymes for synthesizing ceramide. Identification of the pathway for sphingomyelin synthesis in brain will be attempted. The value of a new video densitometer in lipid analysis will be determined.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS003192-31
Application #
3393285
Study Section
Neurology A Study Section (NEUA)
Project Start
1979-02-01
Project End
1992-01-31
Budget Start
1990-02-01
Budget End
1992-01-31
Support Year
31
Fiscal Year
1990
Total Cost
Indirect Cost

  Institution

Name
University of Michigan Ann Arbor
Department
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109

  Publications

Shukla, A; Shukla, G S; Radin, N S (1992) Control of kidney size by sex hormones: possible involvement of glucosylceramide. Am J Physiol 262:F24-9
Barbour, S; Edidin, M; Felding-Habermann, B et al. (1992) Glycolipid depletion using a ceramide analogue (PDMP) alters growth, adhesion, and membrane lipid organization in human A431 cells. J Cell Physiol 150:610-9
Fenderson, B A; Ostrander, G K; Hausken, Z et al. (1992) A ceramide analogue (PDMP) inhibits glycolipid synthesis in fish embryos. Exp Cell Res 198:362-6
Abe, A; Inokuchi, J; Jimbo, M et al. (1992) Improved inhibitors of glucosylceramide synthase. J Biochem 111:191-6
Mahdiyoun, S; Deshmukh, G D; Abe, A et al. (1992) Decreased formation of inositol trisphosphate in Madin-Darby canine kidney cells under conditions of beta-glucosidase inhibition. Arch Biochem Biophys 292:506-11
Radin, N S; Shukla, G S (1991) Ultrasonic baths as substitutes for shaking incubator baths. Enzyme 45:67-70
Shukla, A; Radin, N S (1991) Metabolism of D-[3H]threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol, an inhibitor of glucosylceramide synthesis, and the synergistic action of an inhibitor of microsomal monooxygenase. J Lipid Res 32:713-22
Shukla, G S; Shukla, A; Radin, N S (1991) Gangliosides inhibit glucosylceramide synthase: a possible role in ganglioside therapy. J Neurochem 56:2125-32
Shayman, J A; Radin, N S (1991) Structure and function of renal glycosphingolipids. Am J Physiol 260:F291-302
Shayman, J A; Deshmukh, G D; Mahdiyoun, S et al. (1991) Modulation of renal epithelial cell growth by glucosylceramide. Association with protein kinase C, sphingosine, and diacylglycerol. J Biol Chem 266:22968-74

Showing the most recent 10 out of 27 publications