The long-term objective of this research is to understand the biogenesis of peroxisomes in molecular detail.
The aims of this project focus on the machinery for the posttranslational import of proteins into the organelle and on the assembly of the membrane proteins. 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 leavable transit peptides, whereas most mitoochondrial and chloroplast proteins are synthesized as larger precursors with topogenic aminoterminal peptides that are removed proteolytically upon import. Our recent experiments implicate an ATPase and a receptor in the import of proteins into peroxisomes. We have identified eight integral membrane proteins of the organelle and raised antisera against them. We plan to look for additional proteins involved in import. We will identify and characterize the ATPase and putative receptor. We plan to clone and sequence the proteins already implicated in the import machinery (and others that may be discovered) and two major membrane proteins that we have already studied (masses of 22 and 69 kDa). The assembly of these proteins will be investigated. We also intend to continue studies on fibroblasts from Zellweger syndrome - our recent data suggests that this disease may be due to a defect in the import machinery.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37DK019394-16
Application #
3483293
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1976-05-01
Project End
1994-06-30
Budget Start
1992-07-01
Budget End
1994-06-30
Support Year
16
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Mount Sinai School of Medicine
Department
Type
Schools of Medicine
DUNS #
City
New York
State
NY
Country
United States
Zip Code
10029
Nair, Devi M; Purdue, P Edward; Lazarow, Paul B (2004) Pex7p translocates in and out of peroxisomes in Saccharomyces cerevisiae. J Cell Biol 167:599-604
Lazarow, Paul B (2003) Peroxisome biogenesis: advances and conundrums. Curr Opin Cell Biol 15:489-97
Yang, X; Purdue, P E; Lazarow, P B (2001) Eci1p uses a PTS1 to enter peroxisomes: either its own or that of a partner, Dci1p. Eur J Cell Biol 80:126-38
Purdue, P E; Lazarow, P B (2001) Peroxisome biogenesis. Annu Rev Cell Dev Biol 17:701-52
Purdue, P E; Lazarow, P B (2001) Pex18p is constitutively degraded during peroxisome biogenesis. J Biol Chem 276:47684-9
Santos, M J; Henderson, S C; Moser, A B et al. (2000) Peroxisomal ghosts are intracellular structures distinct from lysosomal compartments in Zellweger syndrome: a confocal laser scanning microscopy study. Biol Cell 92:85-94
Purdue, P E; Skoneczny, M; Yang, X et al. (1999) Rhizomelic chondrodysplasia punctata, a peroxisomal biogenesis disorder caused by defects in Pex7p, a peroxisomal protein import receptor: a minireview. Neurochem Res 24:581-6
Purdue, P E; Yang, X; Lazarow, P B (1998) Pex18p and Pex21p, a novel pair of related peroxins essential for peroxisomal targeting by the PTS2 pathway. J Cell Biol 143:1859-69
Purdue, P E; Zhang, J W; Skoneczny, M et al. (1997) Rhizomelic chondrodysplasia punctata is caused by deficiency of human PEX7, a homologue of the yeast PTS2 receptor. Nat Genet 15:381-4
Zhang, J W; Lazarow, P B (1996) Peb1p (Pas7p) is an intraperoxisomal receptor for the NH2-terminal, type 2, peroxisomal targeting sequence of thiolase: Peb1p itself is targeted to peroxisomes by an NH2-terminal peptide. J Cell Biol 132:325-34

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