Pex5p, which is the import receptor for peroxisomal matrix proteins harboring a type I signal sequence (PTS1), is mono- and polyubiquitinated in Saccharomyces cerevisiae. We identified Pex5p as a molecular target for Pex4p-dependent monoubiquitination and demonstrated that either poly- or monoubiquitination of the receptor is required for the ATP-dependent release of the protein from the peroxisomal membrane to the cytosol as part of the receptor cycle. Therefore, the energy requirement of the peroxisomal import pathway has to be extended by a second ATP-dependent step, namely receptor monoubiquitination.
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http://dx.doi.org/10.1083/jcb.200611012 | DOI Listing |
Cells
January 2025
Biosciences, Faculty of Health and Life Sciences, University of Exeter, Exeter EX4 4QD, UK.
Peroxisomes are ubiquitous, dynamic, oxidative organelles with key functions in cellular lipid metabolism and redox homeostasis. They have been linked to healthy ageing, neurodegeneration, cancer, the combat of pathogens and viruses, and infection and immune responses. Their biogenesis relies on several peroxins (encoded by genes), which mediate matrix protein import, membrane assembly, and peroxisome multiplication.
View Article and Find Full Text PDFPlant Cell Physiol
January 2025
University of Münster, Department of Biology, Institute of Plant Biology and Biotechnology, Molecular Physiology of Plants, Schlossplatz 7, 48149 Münster, Germany.
The oxidative pentose phosphate pathway (OPPP) plays an important role for the generation of reducing power in all eukaryotes. In plant cells the OPPP operates in several cellular compartments, but as full cycle only in the plastid stroma where it is essential. As suggested by our recent results, OPPP reactions are also mandatory inside peroxisomes, at least during fertilisation.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
The PEX1/PEX6 AAA-ATPase is required for the biogenesis and maintenance of peroxisomes. Mutations in and disrupt peroxisomal matrix protein import and are the leading cause of Peroxisome Biogenesis Disorders (PBDs). The most common disease-causing mutation in PEX1 is the PEX1 allele, which results in a reduction of peroxisomal protein import.
View Article and Find Full Text PDFNat Metab
December 2024
Department of Biomedicine, University of Bergen, Bergen, Norway.
The coenzyme NAD is consumed by signalling enzymes, including poly-ADP-ribosyltransferases (PARPs) and sirtuins. Ageing is associated with a decrease in cellular NAD levels, but how cells cope with persistently decreased NAD concentrations is unclear. Here, we show that subcellular NAD pools are interconnected, with mitochondria acting as a rheostat to maintain NAD levels upon excessive consumption.
View Article and Find Full Text PDFMol Metab
December 2024
Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea. Electronic address:
Objectives: Dysregulation of lipid homeostasis pathway causes many liver diseases, including hepatic steatosis. One of the primary factors contributing to lipid accumulation is fatty acid uptake by the liver. Transmembrane protein 135 (TMEM135), which exists in mitochondria and peroxisomes, participates in intracellular lipid metabolism.
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