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Insight into the antifungal mechanism of Neosartorya fischeri antifungal protein.

Virágh M, Marton A, Vizler C, Tóth L, Vágvölgyi C, Marx F, Galgóczy L - Protein Cell (2015)

Bottom Line: NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis.In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction.Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.

ABSTRACT
Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.

No MeSH data available.


Related in: MedlinePlus

Tentative model for the antifungal mechanism ofNeosartorya fischeriNFAPinAspergillus nidulansmodified from Binder et al.(2010; 2011) forPenicillium chrysogenumPAF andAspergillus giganteusA3274 AFPNN5353, respectively. 8-Br-cAMP: 8-bromoadenosine 3’,5’-cyclic monophosphate, AC: adenylate cyclase, cAMP: cyclic adenosine monophosphate, CFW: calcofluor white, Mpk: mitogen activated protein kinase, Pka: protein kinase A, Pkc: protein kinase C, RhoA: small GTP binding protein, RlmA: transcription factor, TFs: transcription factors
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Fig3: Tentative model for the antifungal mechanism ofNeosartorya fischeriNFAPinAspergillus nidulansmodified from Binder et al.(2010; 2011) forPenicillium chrysogenumPAF andAspergillus giganteusA3274 AFPNN5353, respectively. 8-Br-cAMP: 8-bromoadenosine 3’,5’-cyclic monophosphate, AC: adenylate cyclase, cAMP: cyclic adenosine monophosphate, CFW: calcofluor white, Mpk: mitogen activated protein kinase, Pka: protein kinase A, Pkc: protein kinase C, RhoA: small GTP binding protein, RlmA: transcription factor, TFs: transcription factors

Mentions: The antifungal mechanism of NFAP proved to be independent from the RhoA and PkcA, members of the CWI pathway. The small GTPase RhoA is an essential protein involved in the polar growth (Guest et al., 2004). PkcA plays a role in the polarity establishment independently of MpkA (Katayama et al., 2012) and in the suppression of apoptosis via MpkA (Katayama et al., 2012) (Fig. 3). Similarly, the toxicity of the P.chrysogenum antifungal protein PAF was also shown to be independent from RhoA, instead inhibition of RhoA-GAP targets was supposed (Binder et al., 2010). In contrast to NFAP, PAF possibly inactivates the Pkc signalling (Binder et al., 2010). Binder et al. (2011) suggested that the toxicity of AFPNN5353 is transmitted by RhoA-GAP targets and not by RhoA itself. The role of RhoA-GAP targets in the NFAP toxicity is awaiting further investigations. In our study NFAP did not induce the CWI pathway in A. nidulans similar to PAF (Binder et al., 2010). In contrast, AFP and AFPNN5353 activates the CWI pathway by increasing the MpkA/RlmA-activated α-glucan synthase agsA expression, a main enzyme in the cell wall remodelling of A. niger (Hagen et al., 2007; Binder et al., 2011) (Fig. 3).Figure 3


Insight into the antifungal mechanism of Neosartorya fischeri antifungal protein.

Virágh M, Marton A, Vizler C, Tóth L, Vágvölgyi C, Marx F, Galgóczy L - Protein Cell (2015)

Tentative model for the antifungal mechanism ofNeosartorya fischeriNFAPinAspergillus nidulansmodified from Binder et al.(2010; 2011) forPenicillium chrysogenumPAF andAspergillus giganteusA3274 AFPNN5353, respectively. 8-Br-cAMP: 8-bromoadenosine 3’,5’-cyclic monophosphate, AC: adenylate cyclase, cAMP: cyclic adenosine monophosphate, CFW: calcofluor white, Mpk: mitogen activated protein kinase, Pka: protein kinase A, Pkc: protein kinase C, RhoA: small GTP binding protein, RlmA: transcription factor, TFs: transcription factors
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4491047&req=5

Fig3: Tentative model for the antifungal mechanism ofNeosartorya fischeriNFAPinAspergillus nidulansmodified from Binder et al.(2010; 2011) forPenicillium chrysogenumPAF andAspergillus giganteusA3274 AFPNN5353, respectively. 8-Br-cAMP: 8-bromoadenosine 3’,5’-cyclic monophosphate, AC: adenylate cyclase, cAMP: cyclic adenosine monophosphate, CFW: calcofluor white, Mpk: mitogen activated protein kinase, Pka: protein kinase A, Pkc: protein kinase C, RhoA: small GTP binding protein, RlmA: transcription factor, TFs: transcription factors
Mentions: The antifungal mechanism of NFAP proved to be independent from the RhoA and PkcA, members of the CWI pathway. The small GTPase RhoA is an essential protein involved in the polar growth (Guest et al., 2004). PkcA plays a role in the polarity establishment independently of MpkA (Katayama et al., 2012) and in the suppression of apoptosis via MpkA (Katayama et al., 2012) (Fig. 3). Similarly, the toxicity of the P.chrysogenum antifungal protein PAF was also shown to be independent from RhoA, instead inhibition of RhoA-GAP targets was supposed (Binder et al., 2010). In contrast to NFAP, PAF possibly inactivates the Pkc signalling (Binder et al., 2010). Binder et al. (2011) suggested that the toxicity of AFPNN5353 is transmitted by RhoA-GAP targets and not by RhoA itself. The role of RhoA-GAP targets in the NFAP toxicity is awaiting further investigations. In our study NFAP did not induce the CWI pathway in A. nidulans similar to PAF (Binder et al., 2010). In contrast, AFP and AFPNN5353 activates the CWI pathway by increasing the MpkA/RlmA-activated α-glucan synthase agsA expression, a main enzyme in the cell wall remodelling of A. niger (Hagen et al., 2007; Binder et al., 2011) (Fig. 3).Figure 3

Bottom Line: NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis.In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction.Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.

ABSTRACT
Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disrupting-effect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.

No MeSH data available.


Related in: MedlinePlus