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IP7-SPX Domain Interaction Controls Fungal Virulence by Stabilizing Phosphate Signaling Machinery.
mBio. 2020 10 20; 11(5)MBIO

Abstract

In the human-pathogenic fungus Cryptococcus neoformans, the inositol polyphosphate signaling pathway is critical for virulence. We recently demonstrated the key role of the inositol pyrophosphate IP7 (isomer 5-PP-IP5) in driving fungal virulence; however, the mechanism of action remains elusive. Using genetic and biochemical approaches, and mouse infection models, we show that IP7 synthesized by Kcs1 regulates fungal virulence by binding to a conserved lysine surface cluster in the SPX domain of Pho81. Pho81 is the cyclin-dependent kinase (CDK) inhibitor of the phosphate signaling (PHO) pathway. We also provide novel mechanistic insight into the role of IP7 in PHO pathway regulation by demonstrating that IP7 functions as an intermolecular "glue" to stabilize Pho81 association with Pho85/Pho80 and, hence, promote PHO pathway activation and phosphate acquisition. Blocking IP7-Pho81 interaction using site-directed mutagenesis led to a dramatic loss of fungal virulence in a mouse infection model, and the effect was similar to that observed following PHO81 gene deletion, highlighting the key importance of Pho81 in fungal virulence. Furthermore, our findings provide additional evidence of evolutionary divergence in PHO pathway regulation in fungi by demonstrating that IP7 isomers have evolved different roles in PHO pathway control in C. neoformans and nonpathogenic yeast.IMPORTANCE Invasive fungal diseases pose a serious threat to human health globally with >1.5 million deaths occurring annually, 180,000 of which are attributable to the AIDS-related pathogen, Cryptococcus neoformans Here, we demonstrate that interaction of the inositol pyrophosphate, IP7, with the CDK inhibitor protein, Pho81, is instrumental in promoting fungal virulence. IP7-Pho81 interaction stabilizes Pho81 association with other CDK complex components to promote PHO pathway activation and phosphate acquisition. Our data demonstrating that blocking IP7-Pho81 interaction or preventing Pho81 production leads to a dramatic loss in fungal virulence, coupled with Pho81 having no homologue in humans, highlights Pho81 function as a potential target for the development of urgently needed antifungal drugs.

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Authors+Show Affiliations

Desmarini D
Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia. Sydney Medical School-Westmead, University of Sydney, Sydney, NSW, Australia. Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.
Lev S
Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia. Sydney Medical School-Westmead, University of Sydney, Sydney, NSW, Australia. Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.
Furkert D
Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany.
Crossett B
Sydney Mass Spectrometry, University of Sydney, Sydney, NSW, Australia.
Saiardi A
Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, United Kingdom.
Kaufman-Francis K
Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia. Sydney Medical School-Westmead, University of Sydney, Sydney, NSW, Australia. Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.
Li C
Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.
Sorrell TC
Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia. Sydney Medical School-Westmead, University of Sydney, Sydney, NSW, Australia. Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.
Wilkinson-White L
School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia.
Matthews J
School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia.
Fiedler D
Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany.
Djordjevic JT
Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia julianne.djordjevic@sydney.edu.au. Sydney Medical School-Westmead, University of Sydney, Sydney, NSW, Australia. Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.

MeSH

AnimalsCryptococcus neoformansFemaleHumansInositol PhosphatesMice, Inbred C57BLMutagenesis, Site-DirectedPhosphotransferases (Phosphate Group Acceptor)PyrophosphatasesRepressor ProteinsSignal TransductionVirulence

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

33082258

Citation

Desmarini, Desmarini, et al. "IP7-SPX Domain Interaction Controls Fungal Virulence By Stabilizing Phosphate Signaling Machinery." MBio, vol. 11, no. 5, 2020.
Desmarini D, Lev S, Furkert D, et al. IP7-SPX Domain Interaction Controls Fungal Virulence by Stabilizing Phosphate Signaling Machinery. mBio. 2020;11(5).
Desmarini, D., Lev, S., Furkert, D., Crossett, B., Saiardi, A., Kaufman-Francis, K., Li, C., Sorrell, T. C., Wilkinson-White, L., Matthews, J., Fiedler, D., & Djordjevic, J. T. (2020). IP7-SPX Domain Interaction Controls Fungal Virulence by Stabilizing Phosphate Signaling Machinery. MBio, 11(5). https://doi.org/10.1128/mBio.01920-20
Desmarini D, et al. IP7-SPX Domain Interaction Controls Fungal Virulence By Stabilizing Phosphate Signaling Machinery. mBio. 2020 10 20;11(5) PubMed PMID: 33082258.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - IP7-SPX Domain Interaction Controls Fungal Virulence by Stabilizing Phosphate Signaling Machinery. AU - Desmarini,Desmarini, AU - Lev,Sophie, AU - Furkert,David, AU - Crossett,Ben, AU - Saiardi,Adolfo, AU - Kaufman-Francis,Keren, AU - Li,Cecilia, AU - Sorrell,Tania C, AU - Wilkinson-White,Lorna, AU - Matthews,Jacqueline, AU - Fiedler,Dorothea, AU - Djordjevic,Julianne Teresa, Y1 - 2020/10/20/ PY - 2020/10/21/entrez PY - 2020/10/22/pubmed PY - 2021/7/20/medline KW - Cryptococcus neoformans KW - IP7 KW - PHO pathway KW - Pho81 KW - SPX domain KW - cyclin-dependent kinase inhibitor KW - fungal virulence KW - inositol polyphosphate KW - inositol pyrophosphate JF - mBio JO - mBio VL - 11 IS - 5 N2 - In the human-pathogenic fungus Cryptococcus neoformans, the inositol polyphosphate signaling pathway is critical for virulence. We recently demonstrated the key role of the inositol pyrophosphate IP7 (isomer 5-PP-IP5) in driving fungal virulence; however, the mechanism of action remains elusive. Using genetic and biochemical approaches, and mouse infection models, we show that IP7 synthesized by Kcs1 regulates fungal virulence by binding to a conserved lysine surface cluster in the SPX domain of Pho81. Pho81 is the cyclin-dependent kinase (CDK) inhibitor of the phosphate signaling (PHO) pathway. We also provide novel mechanistic insight into the role of IP7 in PHO pathway regulation by demonstrating that IP7 functions as an intermolecular "glue" to stabilize Pho81 association with Pho85/Pho80 and, hence, promote PHO pathway activation and phosphate acquisition. Blocking IP7-Pho81 interaction using site-directed mutagenesis led to a dramatic loss of fungal virulence in a mouse infection model, and the effect was similar to that observed following PHO81 gene deletion, highlighting the key importance of Pho81 in fungal virulence. Furthermore, our findings provide additional evidence of evolutionary divergence in PHO pathway regulation in fungi by demonstrating that IP7 isomers have evolved different roles in PHO pathway control in C. neoformans and nonpathogenic yeast.IMPORTANCE Invasive fungal diseases pose a serious threat to human health globally with >1.5 million deaths occurring annually, 180,000 of which are attributable to the AIDS-related pathogen, Cryptococcus neoformans Here, we demonstrate that interaction of the inositol pyrophosphate, IP7, with the CDK inhibitor protein, Pho81, is instrumental in promoting fungal virulence. IP7-Pho81 interaction stabilizes Pho81 association with other CDK complex components to promote PHO pathway activation and phosphate acquisition. Our data demonstrating that blocking IP7-Pho81 interaction or preventing Pho81 production leads to a dramatic loss in fungal virulence, coupled with Pho81 having no homologue in humans, highlights Pho81 function as a potential target for the development of urgently needed antifungal drugs. SN - 2150-7511 UR - https://www.unboundmedicine.com/medline/citation/33082258/IP7_SPX_Domain_Interaction_Controls_Fungal_Virulence_by_Stabilizing_Phosphate_Signaling_Machinery_ DB - PRIME DP - Unbound Medicine ER -