Question

1. Understand the role of each in cell signaling:
   • Adenylyl cyclase, ATP, cAMP, PKA, PIP2 (DAG and IP3), and calcium

Answer 1

Adenylyl cyclase in cell signaling: Adenylate cyclase (AC) converts adenosine triphosphate (ATP) into cAMP,which stimulates cAMP-dependent protein kinase A(PKA). Subsequently specific proteins are phosphorylated by PKA to evoke cellular reactions.

cAMP in cell signaling: cAMP is a second messenger used for intracellular cell transduction, such as transferring into cells the effects of hormones like glucagon and adrenaline, which cannot pass through the plasma membrane. It is also involved in the activation of protein kinase.

PKA in cell signaling: Protein kinase A (PKA) is a protein that is dependent on cyclic AMP(cAMP) and without it, is deactivated. PKA is involved in signal-transduction pathways and phosphorylates proteins by adding a phosphate group. Essentially, PKA is responsible for all the cellular responses induced by cAMP second messenger system.

PIP2 in cell signaling:Phosphatidylinositol 4,5-biphosphate (PIP2) is an essential lipid involved in metabolic processes. It is integral to the cell membrane of all animal and plant cells and acts as a second messenger in a variety of signaling pathways.It is important component of signaling pathway in cell nucleus

Together with diacylglycerol(DAG),IP3 is a second messenger molecule used in signal transduction in biological cells. While DAG stays inside the membrane,IP3 is a Soluble and diffuses through the cell, where it binds to its receptor, which is a calcium channel located in the endoplasmic reticulum.

Calcium in cell signaling: Calcium ions (Ca2+) and phosphate ions have come to rule cell signaling . calcium can act in signal transduction resulting from activation of ion channels or as a second messenger caused by indirect signal transduction pathways such as G protein-coupled receptors.