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Schummer A, Maier R, Gabay-Maskit S, Hansen T, Mühlhäuser WWD, Suppanz I, Fadel A, Schuldiner M, Girzalsky W, Oeljeklaus S, Zalckvar E, Erdmann R, Warscheid B. Pex14p Phosphorylation Modulates Import of Citrate Synthase 2 Into Peroxisomes in Saccharomyces cerevisiae. Front Cell Dev Biol 2020; 8:549451. [PMID: 33042991 PMCID: PMC7522779 DOI: 10.3389/fcell.2020.549451] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/25/2020] [Indexed: 12/16/2022] Open
Abstract
The peroxisomal biogenesis factor Pex14p is an essential component of the peroxisomal matrix protein import machinery. Together with Pex13p and Pex17p, it is part of the membrane-associated peroxisomal docking complex in yeast, facilitating the binding of cargo-loaded receptor proteins for translocation of cargo proteins into the peroxisome. Furthermore, Pex14p is part of peroxisomal import pores. The central role of Pex14p in peroxisomal matrix protein import processes renders it an obvious target for regulatory mechanisms such as protein phosphorylation. To explore this possibility, we examined the state of Pex14p phosphorylation in Saccharomyces cerevisiae. Phos-tag-SDS-PAGE of Pex14p affinity-purified from solubilized membranes revealed Pex14p as multi-phosphorylated protein. Using mass spectrometry, we identified 16 phosphorylation sites, with phosphorylation hot spots located in the N- and C-terminal regions of Pex14p. Analysis of phosphomimicking and non-phosphorylatable variants of Pex14p revealed a decreased import of GFP carrying a peroxisomal targeting signal type 1, indicating a functional relevance of Pex14p phosphorylation in peroxisomal matrix protein import. We show that this effect can be ascribed to the phosphomimicking mutation at serine 266 of Pex14p (Pex14p-S266D). We further screened the subcellular distribution of 23 native GFP-tagged peroxisomal matrix proteins by high-content fluorescence microscopy. Only Cit2p, the peroxisomal isoform of citrate synthase, was affected in the Pex14p-S266D mutant, showing increased cytosolic localization. Cit2p is part of the glyoxylate cycle, which is required for the production of essential carbohydrates when yeast is grown on non-fermentable carbon sources. Pex14p-S266 phosphosite mutants showed reversed growth phenotypes in oleic acid and ethanol with acetyl-CoA formed in peroxisomes and the cytosol, respectively. Overexpression of Cit2p rescued the growth phenotype of yeast cells expressing Pex14p-S266D in oleic acid. Our data indicate that phosphorylation of Pex14p at S266 provides a mechanism for controlling the peroxisomal import of Cit2p, which helps S. cerevisiae cells to adjust their carbohydrate metabolism according to the nutritional conditions.
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Affiliation(s)
- Andreas Schummer
- Faculty of Biology, Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Renate Maier
- Faculty of Biology, Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Shiran Gabay-Maskit
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Tobias Hansen
- Faculty of Medicine, System Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Wignand W D Mühlhäuser
- Faculty of Biology, Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Ida Suppanz
- Faculty of Biology, Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Amir Fadel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Wolfgang Girzalsky
- Faculty of Medicine, System Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Silke Oeljeklaus
- Faculty of Biology, Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Einat Zalckvar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ralf Erdmann
- Faculty of Medicine, System Biochemistry, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Bettina Warscheid
- Faculty of Biology, Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
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Watanabe Y, Kawaguchi K, Saito S, Okabe T, Yonesu K, Egashira S, Kameya M, Morita M, Kashiwayama Y, Imanaka T. An HTRF based high-throughput screening for discovering chemical compounds that inhibit the interaction between Trypanosoma brucei Pex5p and Pex14p. Biochem Biophys Rep 2016; 6:260-265. [PMID: 28955883 PMCID: PMC5600434 DOI: 10.1016/j.bbrep.2016.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/12/2016] [Accepted: 05/06/2016] [Indexed: 11/16/2022] Open
Abstract
The glycosome, a peroxisome-related organelle, is essential for the growth and survival of trypanosomatid protozoa. In glycosome biogenesis, Pex5p recognizes newly synthesized glycosomal matrix proteins via peroxisome-targeting signal type-1 (PTS-1) and transports them into glycosomes through an interaction with Pex14p, a component of the matrix protein import machinery on the glycosomal membrane. Knockdown of the PEX5 or PEX14 with RNAi has been shown to inhibit the growth of Trypanosoma brucei. Thus, compounds that inhibit the interaction of TbPex5p–TbPex14p are expected to become lead compounds in the development of anti-trypanosomal drugs. Here, we report a homogenous time-resolved fluorescence (HTRF) assay for the screening of compounds that inhibit the TbPex5p–TbPex14p interaction. The binding of GST-TbPex14p and TbPex5p-His with or without additional compounds was evaluated by measuring the energy transfer of the HTRF pair, using a terbium-labeled anti GST antibody as the donor and an FITC-labeled anti His antibody as the acceptor. The assay was performed in a 384-well plate platform and exhibits a Z’-factor of 0.85–0.91, while the coefficiency of variation is 1.1–7.7%, suggesting it can be readily adapted to a high-throughput format for the automated screening of chemical libraries. We screened 20,800 compounds and found 11 compounds that inhibited energy transfer. Among them, in a pull-down assay one compound exhibited selective inhibition of TbPex5p–TbPex14p without any HsPex5p–HsPex14p interaction. An HTRF-based TbPex5p–TbPex14p interaction assay system was established. A compound was found that selectively inhibits the TbPex5p–TbPex14p interaction. This system is applicable for drug discovery against other glycosomal proteins.
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Affiliation(s)
- Yuichi Watanabe
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Kosuke Kawaguchi
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Syuken Saito
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Takayoshi Okabe
- Drug Discovery Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kiyoaki Yonesu
- Drug Discovery Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shinichiro Egashira
- Drug Discovery Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masafumi Kameya
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Masashi Morita
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Yoshinori Kashiwayama
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Tsuneo Imanaka
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
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Tamura S, Matsumoto N, Takeba R, Fujiki Y. AAA peroxins and their recruiter Pex26p modulate the interactions of peroxins involved in peroxisomal protein import. J Biol Chem 2014; 289:24336-46. [PMID: 25016021 DOI: 10.1074/jbc.m114.588038] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pex1p and Pex6p are required for the relocation of the import receptor Pex5p from the peroxisomal membrane to the cytosol. We herein show that mammalian Pex26p directly binds to Pex14p, the initial docking receptor of Pex5p, and interacts with Pex5p via Pex14p. The binding affinity of Pex26p to Pex14p is altered by Pex5p. Further evidence suggests that the N-terminal region in Pex26p acts as a scaffold protein to recruit Pex14p·Pex5p complex together with Pex1p·Pex6p complexes on peroxisomes. Pex26p binding to Pex14p was suppressed by overexpression of Pex1p and Pex6p in an ATP-dependent manner, whereas Pex14p was not competed out by Pex1p and Pex6p from Pex26p mutant defective in peroxisomal matrix protein import. These results suggested that peroxisome biogenesis requires Pex1p- and Pex6p-regulated dissociation of Pex14p from Pex26p. Pex1p homo-oligomer directly binds to Pex5p as assessed by a surface plasmon resonance-based assay. Moreover, cytosolic Pex1p is likely to maintain the functional oligomer of Pex5p. Taken together, in the peroxisomal protein import, AAA peroxins modulate the interaction between Pex26p and Pex14p on peroxisome membrane as well as Pex5p oligomer in the cytosol.
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Affiliation(s)
- Shigehiko Tamura
- Faculty of Arts and Science, Kyushu University, Fukuoka 812-8581, Japan and Graduate School of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
| | - Naomi Matsumoto
- Graduate School of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
| | - Ryota Takeba
- Graduate School of Systems Life Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
| | - Yukio Fujiki
- From the Department of Biology, Faculty of Sciences, and
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Tanaka K, Soeda M, Hashimoto Y, Takenaka S, Komori M. Identification of phosphorylation sites in Hansenula polymorpha Pex14p by mass spectrometry. FEBS Open Bio 2012; 3:6-10. [PMID: 23847754 PMCID: PMC3668515 DOI: 10.1016/j.fob.2012.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 10/25/2012] [Accepted: 11/01/2012] [Indexed: 12/20/2022] Open
Abstract
Pex14p is a peroxisomal membrane protein that is involved in both peroxisome biogenesis and selective peroxisome degradation. Previously, we showed that Hansenula polymorpha Pex14p was phosphorylated in vivo. In this study, we identified its phosphorylation site by mass spectrometry. Recombinant His-tagged Pex14p (H6-Pex14p) was overexpressed and purified from the yeast. The protein band corresponding to H6-Pex14p was in-gel digested with trypsin and subjected to LC/MS. As a result of LC/MS, Thr(248) and Ser(258) were identified as the phosphorylated sites. To confirm the phosphorylation sites and explore its functions, we made Ala mutants of the candidate amino acids. In the western blot analysis with anti-Pex14p, S258A mutant gave doublet bands while wild type (WT) and T248A mutants gave triplet bands. Moreover, the double mutant (T248A/S258A) gave a single band. WT and all mutant Pex14p labeled with [(32)P] orthophosphate were immunoprecipitated and analyzed by autoradiography. The phosphorylation of Pex14p was suppressed in S258A mutant, but enhanced in T248A mutant compared to WT. Moreover, the phosphorylated Pex14p was not detected in the T248A/S258A double mutant. All mutants were able to grow on methanol and their matrix proteins (alcohol oxidase and amine oxidase) were mostly localized in peroxisomes. Furthermore all mutants showed selective degradation of peroxisome like WT during the glucose-induced macropexophagy.
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Affiliation(s)
- Katsuhiro Tanaka
- Laboratory of Cellular and Molecular Biology, Department of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku Ourai Kita, Izumisano, Osaka 598-8531, Japan
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