IP7-SPX Domain Interaction Controls Fungal Virulence by Stabilizing Phosphate Signaling Machinery

mBio

Desmarini Desmarini¹  Julianne Teresa Djordjevic¹  Keren Kaufman-Francis¹  Sophie Lev¹  Tania C. Sorrell¹  Dorothea Fiedler²  David Furkert²  Cecilia Li³  Adolfo Saiardi⁴  Lorna Wilkinson-White⁵  Jacqueline Matthews⁵  Ben Crossett⁶ 

[1] Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia;Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany;Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia;Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, United Kingdom;School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia;Sydney Mass Spectrometry, University of Sydney, Sydney, NSW, Australia;

关键词: IP7;    inositol pyrophosphate;    inositol polyphosphate;    SPX domain;    cyclin-dependent kinase inhibitor;    PHO pathway;   

DOI  :  10.1128/mBio.01920-20

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown