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Taxonomic group: fungi / Basidiomycota (Phylum: Basidiomycota)

NCBI PubMed ID: 24835306
Publication DOI: 10.1111/mmi.12642
Journal NLM ID: 8712028
Publisher: Blackwell Publishing
Correspondence: Bölker M <boelker

staff.uni-marburg.de>
Institutions: Department of Biology, Philipps-Universität Marburg, Marburg, Germany, Senckenberg Gesellschaft für Naturforschung, Cluster for Integrative Fungal Research, Frankfurt am Main, Germany, Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany, SYNMIKRO, Philipps-Universität Marburg, Marburg, Germany, LOEWE Excellence Cluster for Integrative FungalResearch, Philipps-Universität Marburg, Marburg, Germany

Many microorganisms secrete surface-active glycolipids. The basidiomycetous fungus Ustilago maydis produces two different classes of glycolipids, mannosylerythritol lipids (MEL) and ustilagic acids (UAs). Here we report that biosynthesis of MELs is partially localized in peroxisomes and coupled to peroxisomal fatty acid degradation. The acyltransferases, Mac1 and Mac2, which acylate mannosylerythritol with fatty acids of different length, contain a type 1 peroxisomal targeting signal (PTS1). We demonstrate that Mac1 and Mac2 are targeted to peroxisomes, while other enzymes involved in MEL production reside in different compartments. Mis-targeting of Mac1 and Mac2 to the cytosol did not block MEL synthesis but promoted production of MEL species with altered acylation pattern. This is in contrast to peroxisome deficient mutants that produced MELs similar to the wild type. We could show that cytosolic targeting of Mac1 and Mac2 reduces the amount of UA presumably due to competition for overlapping substrates. Interestingly, hydroxylated fatty acids characteristic for UAs appear in MELs corroborating cross-talk between both biosynthesis pathways. Therefore, peroxisomal localization of MEL biosynthesis is not only prerequisite for generation of the natural spectrum of MELs, but also facilitates simultaneous assembly of different glycolipids in a single cell.

mannosylerythritol lipid, Pseudozyma flocculosa, extracellular glycolipid

Structure type: monomer ; 720-760
Location inside paper: fig. 1A
Trivial name: mannosylerythritol lipid
Contained glycoepitopes: IEDB_114707,IEDB_137485,IEDB_141181,IEDB_144983,IEDB_152206,IEDB_176772,IEDB_534864,IEDB_983930,SB_44,SB_72

Methods: PCR, TLC, MS, HPLC, statistical analysis, ESI-LTQ-MS, differential interference contrast microscopy, LC/MS, phase contrast microscopy, epifluorescence microscopy
Comments, role: This structure could be mono-acetylated, di-acetylated or non-acetylated. Fatty acid groups can vary amount of C-atoms from 2 to 6 (residue in 2 position) and from 12 to 16 (residue in 3 position).

Related record ID(s): 46319, 46320, 46321, 46322, 46403
NCBI Taxonomy refs (TaxIDs): 5270
Show glycosyltransferases

There is only one chemically distinct structure:

CCCCCCCCCCCCCCCC(=O)O[C@@H]1[C@H](OC(=O)CCCC)[C@H](OC[C@@H](O)[C@@H](O)CO)O[C@H](COC(C)=O)[C@H]1OC(C)=O

SVG MW SMILES 3D mol Ionize

Taxonomic group: plant / Streptophyta (Phylum: Streptophyta)

NCBI PubMed ID: 10448308
Publication DOI: 10.1016/s0959-8049(98)00415-8
Journal NLM ID: 9005373
Publisher: Oxford: Elsevier Science
Correspondence: Lee SK <sklcrs

plaza.snu.ac.kr>
Institutions: College of Pharmacy, Seoul National University, Seoul 151-742, South Korea

In this paper, we present evidence that ginsenoside-Rs4 (G-Rs4; an acetylated analogue of ginsenoside-Rg5), a new ginseng saponin isolated from Panax ginseng C. A. Meyer, elevates protein levels of p53 and p21WAF1, which are associated with the induction of apoptosis in SK-HEP-1 cells. Flow cytometric analyses showed that G-Rs4 initially arrested the cell cycle at the G1/S boundary, but consequently induced apoptosis as evidenced by generating an apoptotic peak. The induction of apoptosis was confirmed by the results of DNA fragmentation assays and alterations in cell morphology after treatment of the cells with G-Rs4. Immunoblot assays showed that G-Rs4 significantly elevated protein levels of p53 and p21WAF1, concurrently with the downregulation of both cyclins E- and A-dependent kinase activities and induction of apoptosis. We suggest that G-Rs4 induces apoptosis, the effect of which is closely related to the downregulation of both cyclins E- and A-dependent kinase activity as a consequence of selectively elevating protein levels of p53 and p21WAF1 in SK-HEP-1 cells.

apoptosis, p53, ginsenoside-Rs4, p21WAF1, CDK2

Structure type: oligomer
Location inside paper: G-Rs4, ginsenoside-Rs4, fig. 1
Trivial name: ginsenoside Rs4
Compound class: saponin glycoside, glycoside
Contained glycoepitopes: IEDB_140628,IEDB_142488,IEDB_146664,IEDB_983931,SB_192

Methods: 13C NMR, 1H NMR, IR, FAB-MS, DNA techniques, radiolabeling, immunoblotting, statistical analysis, flow cytometry, antitumor activity assay, MTT, apoptosis assay, phase contrast microscopy, histone H1 kinase assays
Biological activity: G-Rs4 suppressed cell growth of SK-HEP-1 cells with IC50 value of 20 μM. G-Rs4 arrested cell cycle at the G1/S boundary (apoptotic peak generated after 24 h of treatment with 25 μM) and consequently induced apoptosis ar doses higher than 10 μM. G-Rs4 at dose of 10 μM downregulated activity of both cyclin E- and cyclin A-associated kinases. G-Rs4 elevated protein levels of both p53 and p21WAF1 at effective dose of 10 μM.

NCBI Taxonomy refs (TaxIDs): 4054
Reference(s) to other database(s): GTC:G22842TQ
Show glycosyltransferases

There is only one chemically distinct structure:

CC(=O)OC[C@H]1O[C@@H](O[C@@H]2[C@@H](O)[C@H](O)[C@@H](CO)O[C@H]2O[C@@H]2CC[C@@]3(C)C(CC[C@]4(C)[C@@H]3C[C@H](O)[C@@H]3[C@@H](/C(C)=C/CC=C(C)C)CC[C@]34C)C2(C)C)[C@H](O)[C@@H](O)[C@@H]1O

SVG MW SMILES 3D mol Ionize