AP BIOLOGY

Detailed explanation-1: -The protein kinases belong to the great family of kinases and are responsible for the mechanism of phosphorylation. They are activated by phosphorylation which in turn activates a cascade of events leading to the phosphorylation of different amino acids (3).

Detailed explanation-2: -Activation is mediated by binding of cyclic AMP to the regulatory subunits, which causes the release of the catalytic subunits. cAPK is primarily a cytoplasmic protein, but upon activation it can migrate to the nucleus, where it phosphorylates proteins important for gene regulation. Domain movements in protein kinases.

Detailed explanation-3: -The mechanism of phosphorylation regulation consists of kinases, phosphatases and their substrates phospho-binding proteins. For example, phosphorylation is activated by stimuli such as epigenetic modifications, cytogenetic alterations, genetic mutations or the tumor micro-environment.

Detailed explanation-4: -In many cases, the enzyme being phosphorylated is itself a kinase. The classical example is that protein kinase A phosphorylates the enzyme phosphorylase kinase, which, in turn, phosphorylates glycogen phorphorylase, which leads to breakdown of glycogen in liver and muscle.

Detailed explanation-5: -In the case of phosphorylation, these receptors activate downstream kinases, which then phosphorylate and activate their cognate downstream substrates, including additional kinases, until the specific response is achieved.