Cell Signaling Technology

Product Pathways - Ca / cAMP / Lipid Signaling

PKA C-α Antibody #4782

Applications Reactivity MW (kDa) Source
W IP F H M R 42 Rabbit

Applications Key:  W=Western Blotting  IP=Immunoprecipitation  F=Flow Cytometry
Reactivity Key:  H=Human  M=Mouse  R=Rat
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

PKA C-α Antibody detects endogenous levels of total PKA C-α.

Source / Purification

Polyclonal antibodies are produced by immunizing rabbits with a synthetic peptide (KLH-coupled) derived from the carboxy terminal sequence of human PKA C-α. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from HeLa, C6, PC12 and NIH/3T3 cells, using PKA C-α Antibody.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of HeLa cells, using PKA C-α Antibody (blue) compared to a nonspecific negative control antibody (red).

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, and 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. Within the two R families, two isoforms, α and β (RI-α, RI-β, RII-α and RII-β) exist. 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 is 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 C-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.

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