What is the role of protein kinases in cell signaling transduction?

Protein kinases play a key role in catalyzing the phosphorylation of a protein substrate, thereby facilitating cell signaling transduction. Reversible phosphorylation is a crucial type of modification and is a key feature of cellular signaling. Cell signal transduction includes a multi-step pathway that involves adding or removing phosphate groups in order to activate proteins. Protein kinases are a type of enzyme that transfer phosphate groups from ATP to a protein. This results in a phosphorylation cascade in which one enzyme phosphorylates another, which then phosphorylates another protein, which continues in a sort of chain reaction.