Fungal Kinases With a Sweet Tooth: Pleiotropic Roles of Their Phosphorylated Inositol Sugar Products in the Pathogenicity of Cryptococcus neoformans Present Novel Drug Targeting Opportunities

Front Cell Infect Microbiol. 2019 Jul 15:9:248. doi: 10.3389/fcimb.2019.00248. eCollection 2019.

Abstract

Invasive fungal pathogens cause more than 300 million serious human infections and 1.6 million deaths per year. A clearer understanding of the mechanisms by which these fungi cause disease is needed to identify novel targets for urgently needed therapies. Kinases are key components of the signaling and metabolic circuitry of eukaryotic cells, which include fungi, and kinase inhibition is currently being exploited for the treatment of human diseases. Inhibiting evolutionarily divergent kinases in fungal pathogens is a promising avenue for antifungal drug development. One such group of kinases is the phospholipase C1-dependent inositol polyphosphate kinases (IPKs), which act sequentially to transfer a phosphoryl group to a pre-phosphorylated inositol sugar (IP). This review focuses on the roles of fungal IPKs and their IP products in fungal pathogenicity, as determined predominantly from studies performed in the model fungal pathogen Cryptococcus neoformans, and compares them to what is known in non-pathogenic model fungi and mammalian cells to highlight potential drug targeting opportunities.

Keywords: Cryptococcus neoformans; IP; IP7; PP-IP; inositol polyphosphate kinase; inositol pyrophosphate; signaling; virulence.

Publication types

  • Review

MeSH terms

  • Animals
  • Antifungal Agents / pharmacology*
  • Cryptococcosis / drug therapy
  • Cryptococcosis / microbiology
  • Cryptococcosis / pathology
  • Cryptococcus neoformans / drug effects*
  • Cryptococcus neoformans / genetics
  • Cryptococcus neoformans / metabolism
  • Cryptococcus neoformans / pathogenicity
  • Enzyme Inhibitors / pharmacology
  • Fungal Proteins / antagonists & inhibitors*
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Gene Expression
  • Humans
  • Inositol / metabolism
  • Inositol Phosphates / antagonists & inhibitors*
  • Inositol Phosphates / metabolism
  • Molecular Targeted Therapy / methods
  • Phosphorylation / drug effects
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors*
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Sugars / metabolism
  • Type C Phospholipases / antagonists & inhibitors
  • Type C Phospholipases / genetics
  • Type C Phospholipases / metabolism
  • Virulence
  • Virulence Factors / metabolism*

Substances

  • Antifungal Agents
  • Enzyme Inhibitors
  • Fungal Proteins
  • Inositol Phosphates
  • Sugars
  • Virulence Factors
  • Inositol
  • Phosphotransferases (Alcohol Group Acceptor)
  • Type C Phospholipases
  • phospholipase C1