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Lidbury IDEA, Hitchcock A, Groenhof SRM, Connolly AN, Moushtaq L. New insights in bacterial organophosphorus cycling: From human pathogens to environmental bacteria. Adv Microb Physiol 2024; 84:1-49. [PMID: 38821631 DOI: 10.1016/bs.ampbs.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
In terrestrial and aquatic ecosystems, phosphorus (P) availability controls primary production, with consequences for climate regulation and global food security. Understanding the microbial controls on the global P cycle is a prerequisite for minimising our reliance on non-renewable phosphate rock reserves and reducing pollution associated with excessive P fertiliser use. This recognised importance has reinvigorated research into microbial P cycling, which was pioneered over 75 years ago through the study of human pathogenic bacteria-host interactions. Immobilised organic P represents a significant fraction of the total P pool. Hence, microbes have evolved a plethora of mechanisms to transform this fraction into labile inorganic phosphate, the building block for numerous biological molecules. The 'genomics era' has revealed an extraordinary diversity of organic P cycling genes exist in the environment and studies going 'back to the lab' are determining how this diversity relates to function. Through this integrated approach, many hitherto unknown genes and proteins that are involved in microbial P cycling have been discovered. Not only do these fundamental discoveries push the frontier of our knowledge, but several examples also provide exciting opportunities for biotechnology and present possible solutions for improving the sustainability of how we grow our food, both locally and globally. In this review, we provide a comprehensive overview of bacterial organic P cycling, covering studies on human pathogens and how this knowledge is informing new discoveries in environmental microbiology.
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Affiliation(s)
- Ian D E A Lidbury
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom.
| | - Andrew Hitchcock
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom; Plants, Photosynthesis, and Soil, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Sophie R M Groenhof
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Alex N Connolly
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
| | - Laila Moushtaq
- Molecular Microbiology - Biochemistry and Disease, School of Biosciences, The University of Sheffield, Sheffield, United Kingdom
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Lourdes SR, Gurung R, Giri S, Mitchell CA, McGrath MJ. A new role for phosphoinositides in regulating mitochondrial dynamics. Adv Biol Regul 2024; 91:101001. [PMID: 38057188 DOI: 10.1016/j.jbior.2023.101001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 11/27/2023] [Indexed: 12/08/2023]
Abstract
Phosphoinositides are a minor group of membrane-associated phospholipids that are transiently generated on the cytoplasmic leaflet of many organelle membranes and the plasma membrane. There are seven functionally distinct phosphoinositides, each derived via the reversible phosphorylation of phosphatidylinositol in various combinations on the inositol ring. Their generation and termination is tightly regulated by phosphatidylinositol-kinases and -phosphatases. These enzymes can function together in an integrated and coordinated manner, whereby the phosphoinositide product of one enzyme may subsequently serve as a substrate for another to generate a different phosphoinositide species. This regulatory mechanism not only enables the transient generation of phosphoinositides on membranes, but also more complex sequential or bidirectional conversion pathways, and phosphoinositides can also be transferred between organelles via membrane contacts. It is this capacity to fine-tune phosphoinositide signals that makes them ideal regulators of membrane organization and dynamics, through their recruitment of signalling, membrane altering and lipid transfer proteins. Research spanning several decades has provided extensive evidence that phosphoinositides are major gatekeepers of membrane organization, with roles in endocytosis, exocytosis, autophagy, lysosome dynamics, vesicular transport and secretion, cilia, inter-organelle membrane contact, endosome maturation and nuclear function. By contrast, there has been remarkably little known about the role of phosphoinositides at mitochondria - an enigmatic and major knowledge gap, with challenges in reliably detecting phosphoinositides at this site. Here we review recent significant breakthroughs in understanding the role of phosphoinositides in regulating mitochondrial dynamics and metabolic function.
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Affiliation(s)
- Sonia Raveena Lourdes
- Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Rajendra Gurung
- Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Saveen Giri
- Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Christina A Mitchell
- Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
| | - Meagan J McGrath
- Cancer Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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Devendrakumar KT, Copeland C, Adamchek C, Zhong X, Huang X, Gendron JM, Li X. Arabidopsis Tubby domain-containing F-box proteins positively regulate immunity by modulating PI4Kβ protein levels. THE NEW PHYTOLOGIST 2023; 240:354-371. [PMID: 37571862 PMCID: PMC11114105 DOI: 10.1111/nph.19187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 06/30/2023] [Indexed: 08/13/2023]
Abstract
The Tubby domain, named after the TUBBY protein in mice, binds to phosphatidylinositol 4,5-bisphosphate. Arabidopsis has 11 Tubby domain-containing proteins referred to as Tubby-Like Proteins (TLPs). Of the 11 TLPs, 10 possess the N-terminal F-box domain, which can interact with SKP-like proteins and form SKP1-Cullin-F-box E3 ligase complexes. Although mice TUBBY has been extensively studied, plant TLPs' functions are scarcely detailed. In this study, we show that the Arabidopsis Tubby-like protein 6 (TLP6) and its redundant homologs, TLP1, TLP2, TLP5, and TLP10, positively regulate Arabidopsis immune responses. Furthermore, in an immunoprecipitation mass spectrometry analysis to search for ubiquitination substrates of the TLPs, we identified two redundant phosphoinositide biosynthesis enzymes, phosphatidylinositol 4-kinase β proteins (PI4Kβs), PI4Kβ1 and PI4Kβ2, as TLP interactors. Importantly, TLP6 overexpression lines fully phenocopy the phenotypes of the pi4kβ1,2 mutant, while TLP6 overexpression also leads to increased PI4Kβ2 ubiquitination and reduction in its protein level in a proteasome-dependent manner. Most significantly, TLP6 overexpression does not further enhance the autoimmunity of the pi4kβ1,2 double mutant, supporting the hypothesis that TLP6 targets the PI4Kβs for ubiquitination and degradation. Thus, our study reveals a novel mechanism where TLPs promote plant immune responses by modulating the PI4Kβs protein levels.
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Affiliation(s)
- Karen Thulasi Devendrakumar
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Charles Copeland
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Christopher Adamchek
- Yale Science Building, Yale University, 260 Whitney Ave, New Haven, CT 06511, USA
| | - Xionghui Zhong
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Xingchuan Huang
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Joshua M. Gendron
- Yale Science Building, Yale University, 260 Whitney Ave, New Haven, CT 06511, USA
| | - Xin Li
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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