Cell Signaling Technology

Product Pathways - Metabolism

Phospho-Torc1/Crtc1 (Ser151) Antibody #3359

Applications Reactivity Sensitivity MW (kDa) Source
W H (M) (R) Transfected Only 82 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human  M=Mouse  R=Rat
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-Torc1/Crtc1 (Ser151) Antibody detects transfected levels of Torc1/Crtc1 protein when phosphorylated on Ser151.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to the sequence of human Torc1/Crtc1. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from U-87 MG cells, untransfected or transfected with human wild-type (WT) Torc1 or Torc1 (Ser151Ala), using Phospho-Torc1/Crtc1 (Ser151) Antibody (upper) or DYKDDDDK Tag Antibody (Binds to the same epitope as Sigma's Anti-FLAG® M2 Antibody) #2368 (lower). DYKDDDDK-tagged WT and mutant Torc1 expression vectors were kindly provided by Dr. Marc Montminy at the Salk Institute for Biological Studies.

Background

Glucose homeostasis is regulated by hormones and cellular energy status. Elevations of blood glucose during feeding stimulate insulin release from pancreatic β-cells through a glucose sensing pathway. Feeding also stimulates release of gut hormones such as glucagon-like peptide-1 (GLP-1), which further induces insulin release, inhibits glucagon release and promotes β-cell viability. CREB-dependent transcription likely plays a role in both glucose sensing and GLP-1 signaling (1). The protein Torc2 (transducer of regulated CREB activity 2) functions as a CREB co-activator (2,3) and is implicated in mediating the effects of these two pathways (4). In quiescent cells, Torc2 is phosphorylated at Ser171 and becomes sequestered in the cytoplasm via an interaction with 14-3-3 proteins. Glucose and gut hormones lead to the dephosphorylation of Torc2 and its dissociation from 14-3-3 proteins. Dephosphorylated Torc2 enters the nucleus to promote CREB-dependent transcription. Torc2 plays a key role in the regulation of hepatic gluconeogenic gene transcription in response to hormonal and energy signals during fasting (5). Torc2-related proteins Torc1 and Torc3 also act as CREB co-activators (2,3). Torc1, Torc2 and Torc3 associate with the HTLV Tax protein to promote Tax-dependent transcription of HTLV-1 long terminal repeats (6,7). Torc1 is highly phosphorylated at Ser151 in mouse hypothalamic cells under basal conditions (8). When these cells are exposed to cAMP or a calcium activator, Torc1 is dephosphorylated and translocates into the nucleus (8). Torc1 is essential for energy balance and fertility (8).

  1. Hinke, S.A. et al. (2004) J. Physiol. 558, 369-380.
  2. Conkright, M.D. et al. (2003) Mol. Cell 12, 413-423.
  3. Iourgenko, V. et al. (2003) Proc. Natl. Acad. Sci. USA 100, 12147-12152.
  4. Screaton, R.A. et al. (2004) Cell 119, 61-74.
  5. Koo, S.H. et al. (2005) Nature 437, 1109-1111.
  6. Koga, H. et al. (2004) J. Biol. Chem. 279, 52978-52983.
  7. Siu, Y.T. et al. (2006) J. Virol. 80, 7052-7059.
  8. Altarejos, J.Y. et al. (2008) Nat Med 14, 1112-7.

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