The aim of this research is to investigate the nature and location of the topogenic information that is responsible for targeting proteins to peroxisomes of Candida topicalis. These studies should provide fundamental information about an intriguing problem in cell biology for which no molecular information is yet available. They may also shed light on several human diseases in which peroxisome assembly is defective. Peroxisomes are nearly ubiquitous in eukaryotic cells and have essential functions including fatty acid catabolism, gluconeogenesis, and plasmalogen biosynthesis. Peroxisomes resemble mitochondria and chloroplasts in that the organelles import posttranslationally proteins that are synthesized on free polyribosomes. Peroxisomes differ in that their proteins generally lack cleavable transit peptides, whereas most mitochondrial and chloroplast proteins are synthesized as larger precursors with topogenic aminoterminal peptides that are removed proteolytically upon import. Recently we have made a cDNA library and established an in vitro assay for import of proteins into peroxisomes. With these tools, we now plan to investigate the topogenic information in two peroxisomal proteins, an acyl-CoA oxidase and a 16 kDa polypeptide. Preliminary evidence indicates that sufficient information is present in the carboxyterminal 40% of acyl-CoA oxidase to direct its import into peroxisomes. The location of the targeting sequences within these genes will be determined by deletion analyses and fusions with dihydrofolate reductase. The exact nature of the topogenic sequences will be further investigated by site-directed mutagenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK039684-02
Application #
3239567
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1988-02-01
Project End
1989-11-30
Budget Start
1988-12-01
Budget End
1989-11-30
Support Year
2
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Rockefeller University
Department
Type
Graduate Schools
DUNS #
071037113
City
New York
State
NY
Country
United States
Zip Code
10065
Thieringer, R; Shio, H; Han, Y S et al. (1991) Peroxisomes in Saccharomyces cerevisiae: immunofluorescence analysis and import of catalase A into isolated peroxisomes. Mol Cell Biol 11:510-22
Lazarow, P B (1989) Peroxisome biogenesis. Curr Opin Cell Biol 1:630-4
Szabo, L J; Small, G M; Lazarow, P B (1989) The nucleotide sequence of POX18, a gene encoding a small oleate-inducible peroxisomal protein from Candida tropicalis. Gene 75:119-26