Sandbox 465: Difference between revisions

'''Serine/Threonine-protein kinase''' (STK11) is a tumor suppressor that plays a role in cell metabolism, cell polarity, apoptosis and DNA damage response. STK11 controls the activity of the [[AMP-activated protein kinase]] (AMPK) family members as well as other non AMPK family members. This enzyme acts by phosphorylating the T-loop within AMPK and non AMPK members. The non AMPK family proteins that it phosphorylates are STRADA, [[PTEN]] and possibly [[p53]]/TP53. The AMPK family members it phosphorylates are PRKAA1, PRKAA2, BRSK1, BRSK2, MARK1, MARK2 and others but not MELK. STK11 acts as an upstream regulator by mediating phosphorylation and activation of the AMPK catalytic subunits PRKAA1 and PRKAA2. It also regulates activation of autophagy when cells undergo nutrient deprivation, B-cell differentiation in the germinal center in response to DNA damage and inhibition of signaling pathway that promotes cell growth and proliferation when energy levels are low. Its inhibition of [[PI3K]]/Akt signaling activity in vein endothelial cells induces apoptosis in response to the oxidant peroxynitrite (in vitro). This enzyme also regulates UV-radiation induced DNA damage response and cell polarity by remodeling the actin cytoskeleton. <ref name="Uniprot" />.