âThatâs something we can test. If it does, caspase-1 inhibitors mightâand I emphasize mightâbecome a component of a curative cocktail.â G. Doitsh et al., âCell death by pyroptosis drives CD4 T-cell depletion in HIV-1 infection,â Nature, doi:10.1038/nature12940, 2013.
Decades ago it was believed that a cascade of enzymes controls the activity of HMG-CoA reductase: an HMG-CoA reductase kinase was thought to inactivate the enzyme, and the kinase in turn was held to be activated via phosphorylation by HMG-CoA reductase kinase kinase.
Some of the tyrosine residues can be tagged (at the hydroxyl group) with a phosphate group (phosphorylated) by protein kinases. In its phosphorylated form, tyrosine is called phosphotyrosine. Tyrosine phosphorylation is considered to be one of the key steps in signal transduction and regulation of enzymatic activity.