Cell Signaling Technology

Product Pathways - Jak/Stat Pathway

Phospho-Jak2 (Tyr221) Antibody #3774

Applications Reactivity Sensitivity MW (kDa) Source
W H M (R) Endogenous 125 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-Jak2 (Tyr221) Antibody detects endogenous levels of Jak2 only when phosphorylated at Tyr221.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Tyr221 of human Jak2 protein. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from BaF3 cells, untreated or treated with IL-3 (5 minutes), using Phospho-Jak2 (Tyr221) Antibody #3774 (top) or total Jak2 (D2E12) XP® Rabbit mAb #3230 (bottom).

Background

Members of the Janus family of tyrosine kinases (Jak1, Jak2, Jak3, and Tyk2) are activated by ligands binding to a number of associated cytokine receptors (1). Upon cytokine receptor activation, Jak proteins become autophosphorylated and phosphorylate their associated receptors to provide multiple binding sites for signaling proteins. These associated signaling proteins, such as Stats (2), Shc (3), insulin receptor substrates (4), and focal adhesion kinase (FAK) (5), typically contain SH2 or other phospho-tyrosine-binding domains.

Jak2 is autophosphorylated at Tyr1007/1008 in the putative activation loop during cytokine signaling (6). Tyr221 and 570 have also been shown to be prominent sites for autophosphorylation (7,8). Mutational analysis suggests that phosphorylation at Tyr221 may increase kinase activity, while phosphorylation at Tyr570, which lies within the JH2 inhibitory domain, may contribute to inhibiting Jak2 activity. In addition, Tyr813 was identified as a site for autophosphorylation critical for the activation of Jak2 by the SH2 domain-containing protein SH2-B β (9).

  1. Leonard, W.J. and O'Shea, J.J. (1998) Annu Rev Immunol 16, 293-322.
  2. Darnell, J.E. (1997) Science 277, 1630-5.
  3. VanderKuur, J. et al. (1995) J Biol Chem 270, 7587-93.
  4. Argetsinger, L.S. et al. (1995) J Biol Chem 270, 14685-92.
  5. Zhu, T. et al. (1998) J Biol Chem 273, 10682-9.
  6. Gauzzi, M.C. et al. (1996) J Biol Chem 271, 20494-500.
  7. Argetsinger, L.S. et al. (2004) Mol Cell Biol 24, 4955-67.
  8. Feener, E.P. et al. (2004) Mol Cell Biol 24, 4968-78.
  9. Kurzer, J.H. et al. (2004) Mol Cell Biol 24, 4557-70.

Application References

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Companion Products

This product is sold under license from Chemicon, Inc., U.S. Patent No. 5,658,791.

For Research Use Only. Not For Use In Diagnostic Procedures.

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