ULK1
ULK1 (unc-51 like autophagy activating kinase 1, also known as ATG1 or ATG1A) is a serine/threonine-protein kinase that drives autophagy in response to starvation. It acts upstream of PIK3C3 to control the formation of autophagophores, the precursors of autophagosomes. Browse Assay Genie's current range of ULK1 research reagents below, or read on for the biology behind the target.
ULK1 is a serine/threonine-protein kinase involved in autophagy triggered by starvation. It acts upstream of the phosphatidylinositol 3-kinase PIK3C3 to regulate the formation of autophagophores. ULK1 sits within regulatory feedback loops: it is both a downstream effector and a negative regulator of mammalian target of rapamycin complex 1 (mTORC1), through its interaction with RPTOR. AMPK activates ULK1 by phosphorylation, and ULK1 in turn phosphorylates the AMPK subunits PRKAA1, PRKAB2 and PRKAG1, which negatively regulates AMPK activity.
ULK1 phosphorylates several other autophagy regulators. These include SESN2 and SQSTM1, and FLCN, whose phosphorylation promotes autophagy. ULK1 also phosphorylates AMBRA1 in response to autophagy induction, releasing AMBRA1 from its cytoskeletal docking site to induce autophagosome nucleation. Phosphorylation of ATG4B has the opposite effect: it inhibits autophagy by reducing both the proteolytic activation and the delipidation activities of ATG4B. Phosphorylation of ATG13 and RPTOR has been proposed, but the source annotation notes that such data need additional evidence. Beyond autophagy, ULK1 plays a role early in neuronal differentiation and is required for granule cell axon formation.
The ULK1 gene encodes a protein of the protein kinase superfamily, in the Ser/Thr protein kinase family and the APG1/unc-51/ULK1 subfamily. HGNC places it in the autophagy related group and the Unc-51 like kinase family. Its previous names, unc-51-like kinase 1 (C. elegans), reflect its homology to the C. elegans unc-51 gene. NCBI Gene lists identical protein binding, protein serine/threonine kinase and small GTPase binding activities, and describes ULK1 as part of the Atg1/ULK1 kinase complex, located at the cytosol and the phagophore assembly site membrane. The mouse ortholog is Ulk1.
ULK1 acts upstream of PIK3C3 to regulate autophagophore formation, making it a central readout for how autophagosome biogenesis begins.
ULK1 is phosphorylated by AMPK and negatively regulates both AMPK and mTORC1, so it is useful for studying starvation-response feedback loops.
ULK1 plays a role early in neuronal differentiation and is required for granule cell axon formation.
ULK1 phosphorylates targets such as AMBRA1, FLCN, SQSTM1, SESN2 and ATG4B, offering routes to dissect how autophagy is switched on or off.
ULK1 is a serine/threonine kinase that promotes autophagy in response to starvation. It acts upstream of PIK3C3 to regulate autophagophore formation and phosphorylates substrates including AMBRA1, FLCN, SQSTM1 and ATG4B. It also feeds back on AMPK and mTORC1 signalling.
ULK1 is also known as ATG1 and ATG1A. Its HGNC full name is unc-51 like autophagy activating kinase 1, and earlier names were unc-51-like kinase 1 (C. elegans) and unc-51 (C. elegans)-like kinase 1. UniProt lists it as serine/threonine-protein kinase ULK1.
Yes. ULK1 belongs to the APG1/unc-51/ULK1 subfamily, named for the yeast APG1 and C. elegans unc-51 relatives, and the mouse ortholog is Ulk1. Check the datasheet of any product for its validated reactivity.
Other autophagy regulators, ULK complex components and mTOR and AMPK pathway proteins that connect to ULK1 signalling.
Gene and protein annotations from HGNC, NCBI Gene and UniProt O75385; product specifications from Assay Genie datasheets.