Question

Adrenaline binds to GPCR, which increases the level of intracellular cAMP. One of the major intracellular targets of cAMP is PKA. What kind of molecule is PKA?

1) GEF
2) Calcium activated kinase
3) cAMP activated lipid kinase
4) cAMP activated protein kinase

Answer 1

PKA is a cAMP activated protein kinase which is involved in phosphorylating various proteins, altering their activity and playing a critical role in the cellular response to adrenaline, such as glycogen breakdown and energy mobilization.

Step-by-step explanation:

PKA is a cAMP activated protein kinase. When adrenaline binds to GPCR, the level of intracellular cAMP increases, activating PKA. PKA, also known as protein kinase A, is responsible for phosphorylating various proteins, which can alter their function and activity.

In response to adrenaline, which is produced by the adrenal gland, PKA is activated through a signaling pathway. Initially, the hormone binds to ß-adrenergic receptors connected to Gs proteins, which activate adenylyl cyclase. This enzyme converts ATP to cAMP, which then activates PKA.

Activated PKA plays a crucial role in multiple cellular processes, such as glycogen breakdown in muscle cells during the fight or flight response. It phosphorylates enzymes involved in glycogen degradation and inhibits the synthesis of glycogen, providing a quick energy source (glucose) for the cell.