Which second messenger is primarily increased by the action of Protein kinase B?

Protein kinase B (PKB), also known as Akt, is a key player in various signaling pathways that regulate metabolism, cell growth, survival, and other essential cellular processes. The primary pathway that activates PKB involves the phosphatidylinositol-3-kinase (PI3K) signaling pathway. Upon activation of PI3K, this enzyme catalyzes the conversion of phosphatidylinositol 4,5-bisphosphate (PIP2) to phosphatidylinositol 3,4,5-trisphosphate (PIP3).

PIP3 serves as a docking site for PKB, allowing its activation through phosphorylation by the 3-phosphoinositide-dependent protein kinase-1 (PDK1). The increase of PIP3, rather than cGMP, cAMP, or IP3, directly correlates with the action of PKB. Therefore, the relevant second messenger predominantly associated with the activation of PKB is not one of the provided choices.

cGMP and cAMP are cyclic nucleotides involved in different signaling pathways, often related to nitric oxide signaling and adrenergic receptor signaling, respectively. IP3 is part of the phospholipase C pathway, leading