Untersuchungen zum Stoffwechsel und der Biogenese von Peroxisomen
Zusammenfassung der Projektergebnisse
Peroxisomes are single-membrane bound organelles ubiquitous in eukaryotic cells. The central function of peroxisomes from all organisms is the ß-oxidation of fatty acids and the detoxification of the hydrogen peroxide. In mammalian cells, the breakdown of fatty acids is distributed between peroxisomes and mitochondria while in most other organisms the degradation of fatty acids is exclusively taking place in peroxisomes. The consequence of a peroxisomal malfunction is expressed in human peroxisomal disorders, which can be categorized as either single-enzyme disorders or peroxisomal biogenetic defects. Singleenzyme disorders, for example the Refsum disease is caused by a defect of phytanoyl CoA hydroxylase, or X-linked adrenoleukodystrophy caused by a defect in a peroxisomal ATP- transporter. In contrast, biogenetic defects are mostly caused by mutations in the peroxisomal biogenesis genes, the PEX genes that code for peroxins. According to the granted proposal five lines of research were pursued and the following results were achieved in the last funding period: • Identification of peroxisomal proteins and yeast mutants affect in peroxisomal function and/or biogenesis 4755 yeast mutants were screened and 56 mutant strains were identified exhibitint a defect in peroxisome function. • Characterization and functional analysis of newly identified components of the peroxisomal lipid metabolism Proteomic and genetic methods were applied to identify novel peroxisomal proteins. Lpx1p was identified as a novel peroxisomal lipase required for peroxisome morphology. • Functional analysis of the peroxisomal membrane protein Pmp45p and the putative peroxisomal ATP/ADP-transporter Pmp35p. Pmp45p, now designated Pex25p proved to be a novel members of the Pex11p-family of proteins involved in peroxisome proliferation. Pmp35p, now named Ant1p, was shown to be a peroxisomal ATP-transporter, which provides ATP for the intraperoxisomal activation of fatty acids. • Characterization of components of the peroxisomal protein import machinery The dynamin-like proteins Vps1p and Dnm1p were shown to play a role in peroxisome proliferation. The interaction sites of PTS2-receptor, co-receptors and components of the peroxisomal docking machinery were identified and characterized. The NMR-structure of the Pex13p-SH3-domain was solved, which revealed a novel interface for binding of components of the peroxisomal protein import machinery. • Functional characterization of the involvement of Pex8p in the peroxisomal protein import We discovered that Pex8p interacts with the PTS2-receptor Pex7p in a co-receptor independent manner. Moreover, we could demonstrate that Pex8p is capable to interact with the docking complex component Pex13p with its C-terminal SH3-domain providing the binding site.
Projektbezogene Publikationen (Auswahl)
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(2001). Identification and functional reconstitution of the yeast peroxisomal adenine nucleotide transporter. EMBO J. 20, 5049-5059
Palmieri, L., Rottensteiner, H., Girzalsky, W., Scarcia, P., Palmieri, F., and Erdmann, R.
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(2001). Identification of peroxisomal membrane proteins of Saccharomyces cerevisiae by mass spectrometry. Electrophoresis 22, 2955-2968
Schäfer, H., Nau, K., Sickmann, A., Erdmann, R., and Meyer, H.E.
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(2002) Interactions of Pex7p and Pex18p/Pex21p with the peroxisomal docking machinery: implications for the first steps in PTS2-protein import. Mol. Cell. Biol. 22, 6056-6069
Stein, K., Schell-Steven, A., Erdmann, R., and Rottensteiner, H.
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(2002) The peroxisomal transporter gene ANT1 is regulated by a deviant oleate response element (ORE): characterization of the signal for fatty acid induction. Biochem J., 365, 109- 117
Rottensteiner, H., Palmieri, L., Hartig, A., Hamilton, B., Ruis, H., Erdmann, R. and Gurvitz, A.
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(2003) Saccharomyces cerevisiae Pip2p-Oaf1p regulates PEX25 transcription through an adenineless ORE. Eur J Biochem. 270, 2013-2022
Rottensteiner, H., Hartig, A., Hamilton, B., Ruis, H., Erdmann, R. and Gurvitz, A.
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(2003). Conserved function of pex11p and the novel pex25p and pex27p in peroxisome biogenesis. Mol. Biol. Cell. 14, 4316-4328
Rottensteiner, H., Stein, K., Sonnenhol, E., and Erdmann, R.
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(2003). Peroxiome biogenesis. Rev. Physiol. Biochem. Pharmacol. 147, 75-121
Eckert, J.H., and Erdmann, R.
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(2003). The ScPex13p SH3 domain exposes two distinct binding sites for Pex5p and Pex14p. J. Mol. Biol. 326, 1427-1435
Pires, J.R., Hong, X., Brockmann, C., Volkmer-Engert, R., Scheider-Mergener, J., Oschkinat, H., and Erdmann, R.
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(2004) The yeast peroxisomal adenine nucleotide transporter: characterization of two transport modes and involvement in DeltapH formation across peroxisomal membranes. Biochem. J., 381, 581-585
Lasorsa, F.M., Scarcia, P., Erdmann, R., Palmieri, F., Rottensteiner, H. and Palmieri, L.
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(2005). Biogenesis of peroxisomes. FEBS J. 272, 2362-2372
Heiland, I., and Erdmann, R.
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(2005). Dynamin-related proteins and Pex11 proteins in peroxisome division and proliferation. FEBS J. 272, 5169-5181
Thoms, S., and Erdmann, R.
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(2006). Dynamin-related proteins Vps1p and Dnm1p control peroxisome abundance in Saccharomyces cerevisiae. Journal of Cell Science 119, 3994- 4001
Kuravi, K., Nagotu, S., Krikken, A.M., Sjollema, K., Deckers, M., Erdmann, R., Veenhuis, M., and van der Klei, I.J.
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(2007). Peroxisomal dynamics. Trends Cell. Biol. 17, 474- 484
Platta, H.W., and Erdmann, R.
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(2007). The peroxisomal protein import machinery. FEBS Lett. 581, 2811-2819
Platta, H.W., and Erdmann, R.
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(2007). Ubiquitination of the peroxisomal import receptor Pex5p is required for its recycling. J. Cell. Biol. 177, 197-204
Platta, H., El Magraoiu, F., Schlee, D., Grunau, S., Girzalsky, W., and Erdmann R.
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(2008). Lpx1p is a peroxisomal lipase required for normal peroxisome morphology. FEBS J. 275, 504-514
Thoms, S., Debelyy, M.O., Nau, K., Meyer, H.E., and Erdmann, R.
