Balancing the Opposing Principles That Govern Peroxisome Homeostasis

Mahalingam, Shanmuga S; Shukla, Nandini; Farré, Jean‐Claude; Zientara‐Rytter, Katarzyna; Subramani, Suresh

doi:10.1016/j.tibs.2020.09.006

Cited by 21 publications

(16 citation statements)

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“…Peroxisomes are dynamic organelles whose biogenesis and degradation are intricately regulated in order to adapt to the changing environment ( Platta and Erdmann, 2007a ; Smith and Aitchison, 2009 ). It has long been accepted that de novo biogenesis of peroxisomes is originated by budding from endoplasmic reticulum ( Tabak et al, 2008 ; Mahalingam et al, 2021 ). The number of peroxisomes could be increased by division of pre-existing ones as well ( Titorenko and Rachubinski, 1998 ; Holroyd and Erdmann, 2001 ; Perry et al, 2009 ).…”

Section: Introductionmentioning

confidence: 99%

Peroxisomes Implicated in the Biosynthesis of Siderophores and Biotin, Cell Wall Integrity, Autophagy, and Response to Hydrogen Peroxide in the Citrus Pathogenic Fungus Alternaria alternata

Chen

Yago

et al. 2021

Front. Microbiol.

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Little is known about the roles of peroxisomes in the necrotrophic fungal plant pathogens. In the present study, a Pex6 gene encoding an ATPase-associated protein was characterized by analysis of functional mutations in the tangerine pathotype of Alternaria alternata, which produces a host-selective toxin. Peroxisomes were observed in fungal cells by expressing a mCherry fluorescent protein tagging with conserved tripeptides serine-lysing-leucine and transmission electron microscopy. The results indicated that Pex6 plays no roles in peroxisomal biogenesis but impacts protein import into peroxisomes. The number of peroxisomes was affected by nutritional conditions and H2O2, and their degradation was mediated by an autophagy-related machinery termed pexophagy. Pex6 was shown to be required for the formation of Woronin bodies, the biosynthesis of biotin, siderophores, and toxin, the uptake and accumulation of H2O2, growth, and virulence, as well as the Slt2 MAP kinase-mediated maintenance of cell wall integrity. Adding biotin, oleate, and iron in combination fully restored the growth of the pex6-deficient mutant (Δpex6), but failed to restore Δpex6 virulence to citrus. Adding purified toxin could only partially restore Δpex6 virulence even in the presence of biotin, oleate, and iron. Sensitivity assays revealed that Pex6 plays no roles in resistance to H2O2 and superoxide, but plays a negative role in resistance to 2-chloro-5-hydroxypyridine (a hydroxyl radical-generating compound), eosin Y and rose Bengal (singlet oxygen-generating compounds), and 2,3,5-triiodobenzoic acid (an auxin transport inhibitor). The diverse functions of Pex6 underscore the importance of peroxisomes in physiology, pathogenesis, and development in A. alternata.

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Section: Introductionmentioning

confidence: 99%

Peroxisomes Implicated in the Biosynthesis of Siderophores and Biotin, Cell Wall Integrity, Autophagy, and Response to Hydrogen Peroxide in the Citrus Pathogenic Fungus Alternaria alternata

Chen

Yago

et al. 2021

Front. Microbiol.

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“…One is the classical growth and division model, in which new peroxisomes are derived from pre-existing peroxisomes. The other model is the de novo model, in which peroxisomes originate from vesicles derived from the endoplasmic reticulum (ER) and/or mitochondria [ 5 ]. A number of genes called peroxins (PEXs) are involved in the various stages of peroxisome biogenesis.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms and Functions of Pexophagy in Mammalian Cells

Wang

2021

Cells

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Peroxisomes play essential roles in diverse cellular metabolism functions, and their dynamic homeostasis is maintained through the coordination of peroxisome biogenesis and turnover. Pexophagy, selective autophagic degradation of peroxisomes, is a major mechanism for removing damaged and/or superfluous peroxisomes. Dysregulation of pexophagy impairs the physiological functions of peroxisomes and contributes to the progression of many human diseases. However, the mechanisms and functions of pexophagy in mammalian cells remain largely unknown compared to those in yeast. This review focuses on mammalian pexophagy and aims to advance the understanding of the roles of pexophagy in human health and diseases. Increasing evidence shows that ubiquitination can serve as a signal for pexophagy, and ubiquitin-binding receptors, substrates, and E3 ligases/deubiquitinases involved in pexophagy have been described. Alternatively, pexophagy can be achieved in a ubiquitin-independent manner. We discuss the mechanisms of these ubiquitin-dependent and ubiquitin-independent pexophagy pathways and summarize several inducible conditions currently used to study pexophagy. We highlight several roles of pexophagy in human health and how its dysregulation may contribute to diseases.

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“…Our knowledge on the biogenesis, dynamics (fission, transport), degradation by autophagy (pexophagy), etc. is still scarce, leaving room for exciting discoveries (Costello and Schrader 2018 ; Islinger et al 2018 ; Mast et al 2020 ; Mahalingam et al 2020 ). Moreover, peroxisomes function in concert with other organelles, including metabolic interaction and signal transduction.…”

Section: Introductionmentioning

confidence: 99%