Would you expect lower or higher levels of PKA in cells trea

Would you expect lower or higher levels of PKA in cells treated with cholera toxin? Why?

Solution

Cholera toxin (CTx), secreted by the gram negative bacterium Vibrio cholera, causes the symptoms observed in cholera, a potentially life-threatening infectious disease in the developing world. Studies have revealed that Cholera toxin catalyzes ADP-ribosylation of Gs protein and results in accumulation of cellular cAMP ,The PKA enzyme is also known as cAMP-dependent enzyme because it is activated only when cAMP is present. Hormones such as glucagon and epinephrine begin the activation cascade (that triggers protein kinase A) by binding to a G protein–coupled receptor (GPCR) on the target cell.All of the findings mentioned above revealed the potential of cholera toxin, a kind of biotoxin, in the differentiation induction of tumor cells. Surprisingly, a possible biological effect of cholera toxin in cancer therapy has, to our knowledge, never been investigated previously. An exploration for the differentiation-inducing and possible therapeutic potential of cholera toxin on malignant glioma is therefore essential.