Endocytosis is a fundamental process in eukaryotic cells important for a variety of cellular functions ranging from the acquisition of certain nutrients, regulation of cell function, including cholesterol synthesis related to atherosclerotic plaque formation in heart disease, and response of the immune system in antibody production. The overall objective of this proposal is to better understand basic molecular events underlying steps of the endocytic process. Our approach is to isolate temperature-sensitive mutants of mammalian cells that are defective in some aspect of endocytosis and then study the mutant cells to gain information about the specific events that are defective.
In specific aim one, we propose a variety of physiological and morphological studies in vivo to characterize a mutant, termed V.24.1, that has defective lysosomes at the defect. In addition, we plan an in vitro approach to investigating protein targeting in the mutant cells.
Specific aim two involves studying in vitro complementation between two other mutants that are defective in endosomal acidification.
In specific aim three we propose to further characterize another mutant, termed 42.2, that has an undefined lesion affecting endocytosis.
Specific aim four involves using a new technique we have devised to isolate mutants expressing temperature-sensitive lesions affecting early steps of endocytic vesicle formation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM034297-08
Application #
3285033
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1985-01-01
Project End
1995-06-30
Budget Start
1993-07-01
Budget End
1994-06-30
Support Year
8
Fiscal Year
1993
Total Cost
Indirect Cost
Name
University of Texas-Dallas
Department
Type
Schools of Arts and Sciences
DUNS #
City
Richardson
State
TX
Country
United States
Zip Code
75080
Chen, Alice; AbuJarour, Ramzey J; Draper, Rockford K (2003) Evidence that the transport of ricin to the cytoplasm is independent of both Rab6A and COPI. J Cell Sci 116:3503-10
Chen, Alice; Hu, Tonghuan; Mikoryak, Carole et al. (2002) Retrograde transport of protein toxins under conditions of COPI dysfunction. Biochim Biophys Acta 1589:124-39
Draper, R K; Hudson, R T; Hu, T (2001) Use of aminoglycoside antibiotics and related compounds to study ADP-ribosylation factor (ARF)/coatomer function in Golgi traffic. Methods Enzymol 329:372-9
Hu, T; Kao, C Y; Hudson, R T et al. (1999) Inhibition of secretion by 1,3-Cyclohexanebis(methylamine), a dibasic compound that interferes with coatomer function. Mol Biol Cell 10:921-33
Hudson, R T; Draper, R K (1997) Interaction of coatomer with aminoglycoside antibiotics: evidence that coatomer has at least two dilysine binding sites. Mol Biol Cell 8:1901-10
Corboy, M J; Draper, R K (1997) Elevation of vacuolar pH inhibits the cytotoxic activity of furin-cleaved exotoxin A. Infect Immun 65:2240-2
Kao, C Y; Draper, R K (1992) Retention of secretory proteins in an intermediate compartment and disappearance of the Golgi complex in an END4 mutant of Chinese hamster ovary cells. J Cell Biol 117:701-15
Wang, R H; Colbaugh, P A; Kuo, P et al. (1992) Novel method for isolating mammalian cells defective in fluid-phase endocytosis. Somat Cell Mol Genet 18:543-51
Park, J E; Draper, R K; Brown, W J (1991) Biosynthesis of lysosomal enzymes in cells of the End3 complementation group conditionally defective in endosomal acidification. Somat Cell Mol Genet 17:137-50
Draper, R K; Goda, Y; Brodsky, F M et al. (1990) Antibodies to clathrin inhibit endocytosis but not recycling to the trans Golgi network in vitro. Science 248:1539-41

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