ULK2
Description
The ULK2 (unc-51 like autophagy activating kinase 2) is a protein-coding gene located on chromosome 17.
ULK2 (Unc-51-like kinase 2) is an enzyme encoded by the ULK2 gene in humans. This gene is located within the Smith-Magenis syndrome region on chromosome 17. ULK2 is a serine/threonine kinase, similar to a kinase found in C. elegans, which is involved in axonal elongation. The protein structure of ULK2 resembles that of its C. elegans counterpart, consisting of an N-terminal kinase domain, a central proline/serine rich (PS) domain, and a C-terminal (C) domain. ULK2 and the GTPase activating protein SynGAP function together in axon formation.
ULK2 is a serine/threonine-protein kinase that plays a critical role in autophagy, a cellular process of self-degradation that helps cells survive under starvation conditions. ULK2 acts upstream of the phosphatidylinositol 3-kinase PIK3C3 to regulate the formation of autophagophores, which are the precursors to autophagosomes. ULK2 is involved in regulatory feedback loops in autophagy, acting both as a downstream effector and a negative regulator of the mammalian target of rapamycin complex 1 (mTORC1) through its interaction with RPTOR. ULK2 is activated via phosphorylation by AMPK, but it also acts as a negative regulator of AMPK through phosphorylation of its subunits PRKAA1, PRKAB2, and PRKAG1. While ULK2 may phosphorylate other proteins such as ATG13/KIAA0652, FRS2, FRS3, and RPTOR, this needs further investigation. ULK2 does not appear to be involved in ammonia-induced autophagy or the autophagic response of cerebellar granule neurons (CGN) to low potassium concentrations. In addition to its role in autophagy, ULK2 also plays a crucial part in early neuronal differentiation and is required for the formation of axons in granule cells. This axonal formation may be governed by Ras-like GTPase signaling and through regulation of Rab5-mediated endocytic pathways within developing axons.
ULK2 is also known as ATG1B, Unc51.2.
