Degradation of transcription factors, c-Jun and c-Fos, by calpain.
c-Jun protein, and AP1/PEA1 transcription factor component, is a typical short-lived protein, and like other short-lived proteins such as c-Fos, contains PEST regions. Calcium-dependent neutral protease (calpain), a candidate for the degradation of PEST-containing proteins, digests c-Jun and c-Fos efficiently in vitro. This is the first demonstration that transcription factors are substrates for calpain. The C-terminal portion of c-Jun is relatively resistant to calpain such that an 18kDa fragment, which includes the DNA binding domain, accumulates under moderate digestion conditions. The activity of c-Jun in cultured cells can be modified by changing the level of calpastatin, an endogenous calpain inhibitor, indicating that c-Jun is also a substrate for calpain in vivo.
Hirai
S
S
Department of Molecular Biology, Tokyo Metropolitan Institute of Medical Science, Japan.
Kawasaki
H
H
Yaniv
M
M
Suzuki
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D002154:Calpain / Q000378:metabolism*; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D013379:Substrate Specificity; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*
D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D004247:DNA; D002154:Calpain