The fungal plasma membrane: a central player in the toxicity of the Penicillium chrysogenum antifungal protein PAF

Ref ID: 18467

Author:

Florentine Marx, Andrea Eigentler, Ulrike Binder,Valéria Tomori,Mónika Nyitrai, ídám Fizil, Gyula Batta

Author address:

Division of Molecular Biology, Biocenter, Innsbruck Medical University, Austria,  
Department of Biochemistry,
University of Debrecen, Hungary  

Full conference title:

11 th European Conference on Fungal Genetics

Abstract:

The cationic antifungal protein PAF inhibits the growth of sensitive filamentous fungi, e.g. Aspergillus nidulans,
Aspergillus fumigatus, Neursopora crassa. The plasma membrane plays a crucial role in binding PAF, regulating ion
channels in response to PAF, transmitting signals into the cell and finally also in PAF uptake. Thus the plasma
membrane might determine at least in part PAF resistance or sensitivity. A microarray8208;based gene expression
analysis in A. fumigatus revealed the deregulation of genes in response to PAF which are directly involved in fatty
acid and lipid synthesis, membrane composition and cell signalling. In accordance, the following pathways were
identified to be significantly deregulated by PAF treatment (KEGG GSEA, p<0.05): glycerophospholipid metabolism (afm00641), inositol phosphate metabolism (afm00562) and phosphatidylinositol signalling (afm04070). A change in the expression of genes involved in the synthesis of the plasma membrane may affect its composition and fluidity and finally its accessibility for PAF pointing towards the attempt of the fungus to survive the antifungal attack. We studied in more detail the interaction of PAF with the plasma membrane and found that PAF binds exclusively to phosphoinositolphosphate (PIP), bis8208; (PIP2) and triphosphates (PIP3) and phosphatidic acid (PA), but not to phospholipids. These properties were further investigated by solution NMR 15 N8208;chemical shift titration (CST) and saturation transfer difference (STD). We could prove by CST that PAF binds to PIP3 with moderate affinity (K=3.600/M). STD experiments revealed that PAF interacts by its aromatic parts with so far unidentified membrane components (putatively high molecular weight proteins).  

Abstract Number: PR1.53

Conference Year: 2012

Link to conference website: http://www.ecfg.info/images/Abstract_Book_Electronic.pdf

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