Cryptococcus neoformans Activates RhoGTPase Proteins Followed by Protein Kinase C, Focal Adhesion Kinase, and Ezrin to Promote Traversal across the Blood-Brain Barrier

Abstract

Background:Cryptococcus neoformans traverses across the BBB to penetrate into the brain. Results: C. neoformans activates RhoGTPases and subsequently PKC␣, focal adhesion kinase, and ezrin in HBMEC. Conclusion: Activation of host signaling proteins promotes Cryptococcus crossing the BBB. Significance: Elucidation of the host signaling events that contributes to cryptococcal BBB traversal is important for a better understanding of its pathogenesis.

Global Reprogramming of Host Kinase Signaling in Response to Fungal Infection

“…1a). Lysates from 60 biologically independent samples of mock or infected host cells were then prepared using methods that isolated host proteins and limited capture and analysis of pathogen-derived components (Kim et al, 2012) (Fig. 1b).…”

“…Mock-infected cells served as controls. Two hours post-infection, the infected cells were washed with cold PBS two times and then lysed with RIPA (Kim et al, 2012) buffer (G Biosciences) supplemented with protease inhibitor tablets (Sigma-Aldrich), phosphatase inhibitor cocktail 2 and phosphatase inhibitor cocktail 3 (Sigma-Aldrich). The lysed cells were collected, vortexed and twice clarified by centrifugation for 15 min at 4°C.…”

From the blood to the brain: avenues of eukaryotic pathogen dissemination to the central nervous system

“…A proteomic survey of human brain endothelial cells following exposure to C. neoformans demonstrated marked changes in the expression of metabolic and cytoskeletal factors, and analysis by transmission electron microscopy revealed structural damage to the organelles as well as cell injury and death [62 ]. Rearrangement of host actin may be a critical step in C. neoformans transcellular passage across the BBB, and evidence supports the targeting of host Rho GTPases and downstream activation of focal adhesion kinase and ezrin by yeast, possibly due to binding to CD44 [63]. Furthermore, the C. neoformans phospholipase Plb1 associates with and activates the Rho GTPase Rac1 for TEM across human brain endothelium [57].…”

The tumor suppressor geneARHI(DIRAS3)inhibits ovarian cancer cell migration through multiple mechanisms

“…FAK mediates cell motility and adhesion turnover through regulation of the RhoGTPases, especially RhoA, Rac-1 and Cdc42. [53][54][55] FAK affects the downregulation of stress fiber formation by activating RhoA activity 40 and upregulates the formation of lamellipodia by activating Rac-1 via a Cas-Crk-DOCK-ELMO complex. 55 Thus, FAK acts as an integrator of cell motility-associated signaling events.…”