Abstract

We will continue to study the structure, functions, and dynamics of the surface membrane components of eukaryotic cells. We have used bacterial and plant toxins as probes to investigate the pathways for the entry and delivery of these toxins into the cytosol of Chinese hamster ovary (CHO) cells. We have employed these toxins to select somatic cell mutants defective in the intoxication process. Studies in the next five years will be directed towards (1) studies on the fatty acylation of membrane glycoproteins in CHO and yeast mutants altered in N- glycosylation; (2) isolation and characterization of CHO mutants resistant to ionophores monensin and nigericin; (3) isolation and characterization of Vero cell mutants defective in diphtheria toxin receptor; and (4) isolation and characterization of CHO mutants defective in the uptake, transport and release of toxins into the cytosol, including the conditionally lethal mutants. Techniques to be employed include molecular and somatic cell genetics and biochemical analysis of the structures, functions and dynamics of membrane components involved in the receptor- mediated endocytosis of toxins. Results from these studies should provide a better understanding of the intracellular protein transport process and the role of post-translational modification of membrane glycoproteins in cellular physiology.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM028810-11
Application #
3276116
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1980-12-01
Project End
1993-08-31
Budget Start
1991-09-01
Budget End
1992-08-31
Support Year
11
Fiscal Year
1991
Total Cost
Indirect Cost

  Institution

Name
Henry M. Jackson Fdn for the Adv Mil/Med
Department
Type
DUNS #
City
Rockville
State
MD
Country
United States
Zip Code
20817

  Publications

Nambiar, M P; Murugesan, R; Wu, H C (1998) Inhibition of the cytotoxicity of protein toxins by a novel plant metabolite, mansonone-D. J Cell Physiol 176:40-9
Nambiar, M P; Wu, H C (1995) Ilimaquinone inhibits the cytotoxicities of ricin, diphtheria toxin, and other protein toxins in Vero cells. Exp Cell Res 219:671-8
Oda, T; Wu, H C (1995) Protective effect of cell-permeable ceramide analogs against modeccin, ricin, Pseudomonas toxin, and diphtheria toxin. Exp Cell Res 221:1-10
Oda, T; Chen, C H; Wu, H C (1995) Ceramide reverses brefeldin A (BFA) resistance in BFA-resistant cell lines. J Biol Chem 270:4088-92
Oda, T; Wu, H C (1994) Effect of lovastatin on the cytotoxicity of ricin, modeccin, Pseudomonas toxin, and diphtheria toxin in brefeldin A-sensitive and -resistant cell lines. Exp Cell Res 212:329-37
Oswald, E; Sugai, M; Labigne, A et al. (1994) Cytotoxic necrotizing factor type 2 produced by virulent Escherichia coli modifies the small GTP-binding proteins Rho involved in assembly of actin stress fibers. Proc Natl Acad Sci U S A 91:3814-8
Nambiar, M P; Oda, T; Chen, C et al. (1993) Involvement of the Golgi region in the intracellular trafficking of cholera toxin. J Cell Physiol 154:222-8
Oda, T; Wu, H C (1993) Cerulenin inhibits the cytotoxicity of ricin, modeccin, Pseudomonas toxin, and diphtheria toxin in brefeldin A-resistant cell lines. J Biol Chem 268:12596-602
Chen, C H; Kuwazuru, Y; Yoshida, T et al. (1992) Isolation and characterization of a brefeldin A-resistant mutant of monkey kidney Vero cells. Exp Cell Res 203:321-8
Sugai, M; Chen, C H; Wu, H C (1992) Staphylococcal ADP-ribosyltransferase-sensitive small G protein is involved in brefeldin A action. J Biol Chem 267:21297-9

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