Proteinase inhibitors I and II from potatoes block UVB-induced AP-1 activity by regulating the AP-1 protein compositional patterns in JB6 cells.
Proteinase inhibitor I (Inh I) and proteinase inhibitor II (Inh II) from potato tubers are effective proteinase inhibitors of chymotrypsin and trypsin. Inh I and Inh II were shown to suppress irradiation-induced transformation in mouse embryo fibroblasts suggesting that they possess anticarcinogenic characteristics. We have previously demonstrated that Inh I and Inh II could effectively block UV irradiation-induced activation of transcription activator protein 1 (AP-1) in mouse JB6 epidermal cells, which mechanistically may explain their anticarcinogenic actions. In the present study, we investigated the effects of Inh I and Inh II on the expression and composition pattern of the AP-1 complex following stimulation by UV B (UVB) irradiation in the JB6 model. We found that Inh I and Inh II specifically inhibited UVB-induced AP-1, but not NFkappaB, activity in JB6 cells. Both Inh I and Inh II up-regulated AP-1 constituent proteins, JunD and Fra-2, and suppressed c-Jun and c-Fos expression and composition in bound AP-1 in response to UVB stimulation. This regulation of the AP-1 protein compositional pattern in response to Inh I or Inh II may be critical for the inhibition of UVB-induced AP-1 activity by these agents found in potatoes.
Liu
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The Hormel Institute, University of Minnesota, 801 16th Avenue NE, Austin, MN 55912, USA.
Chen
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N
Kaji
A
A
Bode
A M
AM
Ryan
C A
CA
Dong
Z
Z
D001483:Base Sequence; D001798:Blood Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D017931:DNA Primers; D016328:NF-kappa B / Q000378:metabolism; D011198:Solanum tuberosum / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000528:radiation effects; D014466:Ultraviolet Rays
D001798:Blood Proteins; D017931:DNA Primers; D016328:NF-kappa B; D018808:Transcription Factor AP-1; C053635:factor XIIa inhibitor