Cell Signaling Technology

Product Pathways - Apoptosis

Phospho-ULK1 (Ser317) Antibody #6887

Applications Reactivity Sensitivity MW (kDa) Source
W M (H) (R) (Mk) (B) Transfected Only 140 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey  B=Bovine
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-ULK1 (Ser317) Antibody recognizes transfected levels of ULK1 protein only when phosphorylated at Ser317.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Ser317 of human ULK1 protein.

Western Blotting

Western Blotting

Western blot analysis of extracts from 293T cells, mock transfected or transfected with a construct overexpressing mouse ULK1 using Phospho-ULK1 (Ser317) Antibody. Membranes were untreated (upper) or treated with Calf Intestinal Phosphatase (CIP) (lower) to demonstrate phospho-specificity.

Background

Two related serine/threonine kinases, UNC-51-like kinase 1 and 2 (ULK1, ULK2), were discovered as mammalian homologs of the C. elegans gene UNC-51 in which mutants exhibited abnormal axonal extension and growth (1-4). Both proteins are widely expressed and contain an amino-terminal kinase domain followed by a central proline/serine rich domain and a highly conserved carboxy-terminal domain. The roles of ULK1 and ULK2 in axon growth have been linked to studies showing that the kinases are localized to neuronal growth cones and are involved in endocytosis of critical growth factors, such as NGF (5). Yeast two-hybrid studies found ULK1/2 associated with modulators of the endocytic pathway, SynGAP and syntenin (6). Structural similarity of ULK1/2 has also been recognized with the yeast autophagy protein Atg1/Apg1 (7). Knockdown experiments using siRNA demonstrated that ULK1 is essential for autophagy (8), a catabolic process for the degradation of bulk cytoplasmic contents (9,10). It appears that Atg1/ULK1 can act as a convergence point for multiple signals that control autophagy (11), and can bind to several autophagy-related (Atg) proteins, regulating phosphorylation states and protein trafficking (12-16).

AMPK, activated during low nutrient conditions, directly phosphorylates ULK1 at multiple sites including Ser317, Ser555, and Ser777 (17,18). Conversely, mTOR, which is a regulator of cell growth and an inhibitor of autophagy, phosphorylates ULK1 at Ser757 and disrupts the interaction between ULK1 and AMPK (17).

  1. Ogura, K. et al. (1994) Genes Dev 8, 2389-400.
  2. Kuroyanagi, H. et al. (1998) Genomics 51, 76-85.
  3. Yan, J. et al. (1998) Biochem Biophys Res Commun 246, 222-7.
  4. Yan, J. et al. (1999) Oncogene 18, 5850-9.
  5. Zhou, X. et al. (2007) Proc Natl Acad Sci USA 104, 5842-7.
  6. Tomoda, T. et al. (2004) Genes Dev 18, 541-58.
  7. Matsuura, A. et al. (1997) Gene 192, 245-50.
  8. Chan, E.Y. et al. (2007) J Biol Chem 282, 25464-74.
  9. Reggiori, F. and Klionsky, D.J. (2002) Eukaryot Cell 1, 11-21.
  10. Codogno, P. and Meijer, A.J. (2005) Cell Death Differ 12 Suppl 2, 1509-18.
  11. Stephan, J.S. and Herman, P.K. (2006) Autophagy 2, 146-8.
  12. Okazaki, N. et al. (2000) Brain Res Mol Brain Res 85, 1-12.
  13. Young, A.R. et al. (2006) J Cell Sci 119, 3888-900.
  14. Kamada, Y. et al. (2000) J Cell Biol 150, 1507-13.
  15. Lee, S.B. et al. (2007) EMBO Rep 8, 360-5.
  16. Hara, T. et al. (2008) J Cell Biol 181, 497-510.
  17. Kim, J. et al. (2011) Nat Cell Biol 13, 132-41.
  18. Egan, D.F. et al. (2011) Science 331, 456-61.

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