Global Reprogramming of Host Kinase Signaling in Response to Fungal Infection

Abstract

Summary Cryptococcus neoformans (Cn) is a deadly fungal pathogen whose intracellular lifestyle is important for virulence. Host mechanisms controlling fungal phagocytosis and replication remain obscure. Here, we perform a global phosphoproteomic analysis of the host response to Cryptococcus infection. Our analysis reveals numerous and diverse host proteins that are differentially phosphorylated following fungal ingestion by macrophages, thereby indicating global reprogramming of host kinase signaling. Notably, phagocytosis of the pathogen activates the host autophagy initiation complex (AIC) and the upstream regulatory components LKB1 and AMPKα1, which regulate autophagy induction through their kinase activities. AMPKα1 deletion in monocytes results in resistance to fungal colonization of mice. Finally, the recruitment of AIC components to nascent Cryptococcus-containing vacuoles (CnCVs) regulates the intracellular trafficking and replication of the pathogen. These findings demonstrate that host AIC regulatory networks confer susceptibility to infection and establish a proteomic resource for elucidating host mechanisms that regulate fungal intracellular parasitism.

RNA Interference Screening Reveals Host CaMK4 as a Regulator of Cryptococcal Uptake and Pathogenesis

“…They are involved in cellular processes ranging from gene regulation, apoptosis, and cytokine release to differentiation and survival of T-lymphocytes and monocyte-derived cells (20,21). Interestingly, a recent study based on phosphoproteomic analysis identified another member of this family, CaMK2, as a protein involved in C. neoformans phagocytosis (22). This work did not yield CaMK2, which may reflect the very distinct approaches of the two studies.…”

Interactions between fungal hyaluronic acid and host CD44 promote internalization by recruiting host autophagy proteins to forming phagosomes

“…Towards addressing this issue, we reported a functional analysis of host factors that regulate the infection, intracellular replication, and non-lytic release of Cn from host cells (Qin et al, 2011). We extended these findings by performing a phosphoproteomic analysis of the host response to Cn infection (Pandey et al, 2017). This analysis demonstrated that host AIC proteins, and upstream regulatory molecules, contribute to the internalization and intracellular replication of the pathogen in macrophages (Pandey et al, 2017).…”

“…We extended these findings by performing a phosphoproteomic analysis of the host response to Cn infection (Pandey et al, 2017). This analysis demonstrated that host AIC proteins, and upstream regulatory molecules, contribute to the internalization and intracellular replication of the pathogen in macrophages (Pandey et al, 2017). This work also raised questions about the cellular and molecular mechanisms by which these proteins contribute to this phenotype.…”

Quantitative Proteomic Profiling of Cryptococcus neoformans

“…Discovery‐based proteomics, which relies on the generation of peptides following enzymatic digestion of proteins, is commonly referred to as “bottom‐up proteomics.” This approach enables the unbiased analysis of biological systems, including regulation of cellular processes and protein secretion, as well as communication patterns among cells (Ball, Bermas, Carruthers‐Lay, & Geddes‐McAlister, ; Sukumaran et al., ). In Cryptococcus neoformans , an opportunistic human fungal pathogen, defining changes in protein abundance provides novel insight into the production of virulence factors and the responses of both the host and pathogen to infection (Geddes et al., , ; Pandey et al., ). Moreover, the role of MS‐based proteomics in drug discovery also promotes its application in defining biological processes or targets relevant during the evolution of antifungal resistance (Geddes‐Mcalister & Shapiro, ; Moloney, Owens, & Doyle, ; Pais, Costa, et al., ; Pais, Pires, et al., ).…”