The intracellular parasite Toxoplasma gondii alternates between a motile invasive and a quiescent intracellular replicative form, yet how these transitions are regulated is unknown. A positive feedback loop involving protein kinase G (PKG) and calcium-dependent PKs (CDPKs) controls motility, invasion, and egress by Toxoplasma gondii, while PKA isoform c1 (PKAc1) counteracts this pathway. Shortly after invasion, PKAc1 is activated by cyclic AMP (cAMP) produced by adenylate cyclases, leading to the suppression of the PKG/CDPK pathway.
View Article and Find Full Text PDFChlamydiae are obligate intracellular Gram-negative bacterial pathogens that undergo an essential, but poorly understood, biphasic developmental cycle transitioning between the infectious elementary body and the replicative reticulate body. Ser/Thr/Tyr phosphorylation has been increasingly recognized for its role in regulating bacterial physiology. spp.
View Article and Find Full Text PDFFront Cell Infect Microbiol
August 2017
are Gram negative bacterial pathogens responsible for disease in humans and economically important domesticated animals. As obligate intracellular bacteria, they must gain entry into a host cell where they propagate within a parasitophorous organelle that serves as an interactive interface between the bacterium and the host. Nutrient acquisition, growth, and evasion of host defense mechanisms occur from this location.
View Article and Find Full Text PDFUnlabelled: Protein phosphorylation has become increasingly recognized for its role in regulating bacterial physiology and virulence. Chlamydia spp. encode two validated Hanks'-type Ser/Thr protein kinases, which typically function with cognate protein phosphatases and appear capable of global protein phosphorylation.
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