AKT includes PH domain, catalytic domain and regulatory domain. AKT is a key protein downstream of PI3K, which exists in the cytoplasm. As the second messenger, PIP3 binds to the intracellular signal proteins AKT contained PH domain and phosphoinositide dependent kinase-1 (PDK1), which promotes the phosphorylation of Ser308 of AKT protein by PDK1 and leads to the activation of AKT. Activation of PI3K leads to the transformation of PIP2 to PIP3. The other is the direct recognition and binding of Ras and p110 to lead to the activation of PI3K. One is the PI3K interacts with a growth factor receptor contained phosphorylated tyrosine residues, resulting in a conformational change of the dimer and activation of PI3K. There are two ways in which PI3K is activated. A variety of growth factors and signal transduction complexes such as fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), human growth factor (HGF), vascular protein I (Ang1) and insulin can initiate the activation of PI3K. Under normal conditions, PI3K is inactivation as the combination of p58 and p110. Among them, class I PI3K, the most widely studied, is a heterodimer composed of a catalytic subunit (p110) and regulatory subunit (P58) (contains SH2 and SH3 domains). PI3K can be divided into three categories, and their structures and functions are different. PI3K exists in the cytoplasm and has the dual activities of protein kinase and phospholipase. In addition, receptor tyrosine kinases (RTKs), phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidylinositol-3,4,5-triphosphate (PIP3) are also involved. The main components of PI3K-Akt signaling pathway are phosphoinositide3-kinase (PI3K) and protein kinase B (AKT/PKB). It is involved in regulating cell metabolism, growth, proliferation, survival, transcription and protein synthesis by affecting the activation of downstream effector molecules. PI3K-Akt signaling pathway is one of the important signal transduction pathways in cells.
0 kommentar(er)
