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Cellular compartmentalization of secondary metabolism.

Kistler HC, Broz K - Front Microbiol (2015)

Bottom Line: Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g., amino acids, acetyl CoA, NADPH), enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors.Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell.We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

View Article: PubMed Central - PubMed

Affiliation: United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, University of Minnesota Saint Paul, MN, USA.

ABSTRACT
Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g., amino acids, acetyl CoA, NADPH), enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

No MeSH data available.


Related in: MedlinePlus

Co-localization of trichothecene biosynthetic enzymes calonectrin oxygenase and trichodiene oxygenase in toxigenic cells. Toxisomes are visualized in a strain of F. graminearum having a GFP-tagged calonectrin oxygenase and a TagRFP-T-tagged trichodiene oxygenase. (A) Toxigenic cells visualized using DIC microscopy. Note swollen cells with prominent vacuoles; (B) TagRFP-T-tagged trichodiene oxygenase fluorescence at the periphery of toxisomes; (C) GFP calonectrin oxygenase fluorescence at the periphery of toxisomes; (D) combined GFP and TagRFP-T florescence showing toxisome co-localization. Results presented in Menke et al. (2012); figure generated for Menke (2011).
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Figure 4: Co-localization of trichothecene biosynthetic enzymes calonectrin oxygenase and trichodiene oxygenase in toxigenic cells. Toxisomes are visualized in a strain of F. graminearum having a GFP-tagged calonectrin oxygenase and a TagRFP-T-tagged trichodiene oxygenase. (A) Toxigenic cells visualized using DIC microscopy. Note swollen cells with prominent vacuoles; (B) TagRFP-T-tagged trichodiene oxygenase fluorescence at the periphery of toxisomes; (C) GFP calonectrin oxygenase fluorescence at the periphery of toxisomes; (D) combined GFP and TagRFP-T florescence showing toxisome co-localization. Results presented in Menke et al. (2012); figure generated for Menke (2011).

Mentions: Two inducible cytochrome P-450 oxygenases responsible for catalyzing early and late steps in the trichothecene biosynthetic pathway also localize to ~3 μm spherical structures (Figure 4). Both trichodiene oxygenase (Tri4p) and calonectrin oxygenase (Tri1p) contain single predicted membrane anchor sequences and co-localize with each other and to the membrane of structures containing Hmg CoA reductase under inducing conditions (Menke et al., 2013). Because the structures contain both studied toxin biosynthetic enzymes, they have been called “toxisomes” and are the presumptive site of trichothecene assembly. However, it remains unclear whether the structures represent a novel organelle or rather a profoundly reorganized ER responsive to trichothecene induction.


Cellular compartmentalization of secondary metabolism.

Kistler HC, Broz K - Front Microbiol (2015)

Co-localization of trichothecene biosynthetic enzymes calonectrin oxygenase and trichodiene oxygenase in toxigenic cells. Toxisomes are visualized in a strain of F. graminearum having a GFP-tagged calonectrin oxygenase and a TagRFP-T-tagged trichodiene oxygenase. (A) Toxigenic cells visualized using DIC microscopy. Note swollen cells with prominent vacuoles; (B) TagRFP-T-tagged trichodiene oxygenase fluorescence at the periphery of toxisomes; (C) GFP calonectrin oxygenase fluorescence at the periphery of toxisomes; (D) combined GFP and TagRFP-T florescence showing toxisome co-localization. Results presented in Menke et al. (2012); figure generated for Menke (2011).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321598&req=5

Figure 4: Co-localization of trichothecene biosynthetic enzymes calonectrin oxygenase and trichodiene oxygenase in toxigenic cells. Toxisomes are visualized in a strain of F. graminearum having a GFP-tagged calonectrin oxygenase and a TagRFP-T-tagged trichodiene oxygenase. (A) Toxigenic cells visualized using DIC microscopy. Note swollen cells with prominent vacuoles; (B) TagRFP-T-tagged trichodiene oxygenase fluorescence at the periphery of toxisomes; (C) GFP calonectrin oxygenase fluorescence at the periphery of toxisomes; (D) combined GFP and TagRFP-T florescence showing toxisome co-localization. Results presented in Menke et al. (2012); figure generated for Menke (2011).
Mentions: Two inducible cytochrome P-450 oxygenases responsible for catalyzing early and late steps in the trichothecene biosynthetic pathway also localize to ~3 μm spherical structures (Figure 4). Both trichodiene oxygenase (Tri4p) and calonectrin oxygenase (Tri1p) contain single predicted membrane anchor sequences and co-localize with each other and to the membrane of structures containing Hmg CoA reductase under inducing conditions (Menke et al., 2013). Because the structures contain both studied toxin biosynthetic enzymes, they have been called “toxisomes” and are the presumptive site of trichothecene assembly. However, it remains unclear whether the structures represent a novel organelle or rather a profoundly reorganized ER responsive to trichothecene induction.

Bottom Line: Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g., amino acids, acetyl CoA, NADPH), enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors.Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell.We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

View Article: PubMed Central - PubMed

Affiliation: United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, University of Minnesota Saint Paul, MN, USA.

ABSTRACT
Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g., amino acids, acetyl CoA, NADPH), enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

No MeSH data available.


Related in: MedlinePlus