Cell Signaling Technology

Product Pathways - Ca / cAMP / Lipid Signaling

PKA RI-α/β Antibody #3927

Applications Reactivity Sensitivity MW (kDa) Source
W IF-IC H M R Endogenous 48 Rabbit

Applications Key:  W=Western Blotting  IF-IC=Immunofluorescence (Immunocytochemistry)
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

PKA RI-α/β Antibody detects endogenous levels of total PKA RI-α and PKA RI-β protein.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Asn310 of human PKA RI-α. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from U118MG and CAD cells using PKA RI-α/β Antibody.

IF-IC

IF-IC

Confocal immunofluorescent analysis of U-118 MG cells using PKA RI-α/β Antibody (green). Actin filaments have been labeled with DY-554 phalloidin (red). Blue pseudocolor = DRAQ5® #4084 (fluorescent DNA dye).

Background

The second messenger cyclic AMP (cAMP) activates cAMP-dependent protein kinase (PKA or cAPK) in mammalian cells and controls many cellular mechanisms such as gene transcription, ion transport, and protein phosphorylation (1). Inactive PKA is a heterotetramer composed of a regulatory subunit (R) dimer and a catalytic subunit (C) dimer. In this inactive state, the pseudosubstrate sequences on the R subunits block the active sites on the C subunits. Three C subunit isoforms (C-α, C-β, and C-γ) and two families of regulatory subunits (RI and RII) with distinct cAMP binding properties have been identified. The two R families exist in two isoforms, α and β (RI-α, RI-β, RII-α, and RII-β). Upon binding of cAMP to the R subunits, the autoinhibitory contact is eased and active monomeric C subunits are released. PKA shares substrate specificity with Akt (PKB) and PKC, which are characterized by an arginine at position -3 relative to the phosphorylated serine or threonine residue (2). Substrates that present this consensus sequence and have been shown to be phosphorylated by PKA are Bad (Ser155), CREB (Ser133), and GSK-3 (GSK-3α Ser21 and GSK-3β Ser9) (3-5). In addition, combined knock-down of PKA C-α and -β blocks cAMP-mediated phosphorylation of Raf (Ser43 and Ser259) (6). Autophosphorylation and phosphorylation by PDK-1 are two known mechanisms responsible for phosphorylation of the C subunit at Thr197 (7).

  1. Montminy, M. (1997) Annu. Rev. Biochem. 66, 807-822.
  2. Dell'Acqua, M.L. and Scott, J.D. (1997) J. Biol. Chem. 272, 12881-12884.
  3. Tan, Y. et al. (2000) J. Biol. Chem. 275, 25865-25869.
  4. Gonzalez, G.A. and Montminy, M.R. (1989) Cell 59, 675-680.
  5. Fang, X. et al. (2000) Proc. Natl. Acad. Sci. USA 97, 11960-11965.
  6. Dumaz, N. and Marais, R. (2003) J. Biol. Chem. 278, 29819 -29823.
  7. Moore, M.J. et al. (2002) J. Biol. Chem. 277, 47878-47884.

Application References

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Companion Products

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

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