Phosphorylation of c-Raf-1 by protein kinase A interferes with activation.
c-Raf-1 is a serine/threonine-specific protein kinase which is regulated by phosphorylation. A putative c-AMP dependent protein kinase PKA phosphorylation site with the consensus sequence RRXS, Ser43, and a predominant phosphorylation site of c-Raf-1, Ser259, can be phosphorylated by PKA in vitro as shown by comparison of phosphopeptide maps of recombinant wild-type c-Raf-1 and the corresponding mutants. In vivo stimulation of the PKA pathway by treatment of A431 cells with Forskolin results in increase of phosphorylation in Ser43. Forskolin reduces the upshift of c-Raf-1 induced by EGF-treatment. It inhibits the EGF-activation of the c-Raf-1 protein kinase activity tested in vitro with a peptide substrate.
Schramm
K
K
Max-Planck-Institut fuer Molekulare Genetik, Abt. Schuster, Berlin (Dahlem), FRG.
Niehof
M
M
Radziwill
G
G
Rommel
C
C
Moelling
K
K
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D002460:Cell Line; D003001:Cloning, Molecular; D005576:Colforsin / Q000494:pharmacology; D016384:Consensus Sequence; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000302:isolation & purification / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000302:isolation & purification / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism
D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D005576:Colforsin; D000255:Adenosine Triphosphate; D005982:Glutathione Transferase; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D017868:Cyclic AMP-Dependent Protein Kinases