Ca2+-PKC-caspase 3-like protease pathway mediates DNA and nuclear fragmentation in ecdysteroid-induced programmed cell death.
20-Hydroxyecdysone (20E) induces programmed cell death in the anterior silk gland of the silkworm. Here, we report the direct interaction between Ca(2+) and protein kinase C (PKC)-caspase 3-like protease pathway in the 20E-induced cell death. The calcium ionophore can mimic 20E effects in inducing DNA and nuclear fragmentation, but such mimicry is only possible in the glands precultured for 18 h with 20E. The simultaneous presence of translation inhibitor with 20E in the preculture showed that de novo protein synthesis was needed to mimic 20E effects by the calcium ionophore. Both a PKC inhibitor and a caspase 3 inhibitor inhibited the mimicking effects. After substitution of the calcium ionophore for 20E, caspase 3-like protease was fully activated 12h later, and DNA and nuclear fragmentation occurred faster than continuous 20E stimuli. The results show the presence of a Ca(2+)-PKC-caspase 3-like protease pathway in 20E signaling, and possible involvement of the pathway up to the mobilization of Ca(2+) in regulating the timing of cell death in vivo.
Iga
Masatoshi
M
Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan. masatoshi.iga@ugent.be
Manaboon
Manaporn
M
Matsui
Hiroto
H
Sakurai
Sho
S
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D012831:Bombyx / Q000201:enzymology*; D053148:Caspase 3 / Q000378:metabolism*; D002478:Cells, Cultured; D053938:DNA Fragmentation; D026461:Ecdysteroids / Q000494:pharmacology*; D007814:Larva / Q000201:enzymology; D011493:Protein Kinase C / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors
D026461:Ecdysteroids; D011493:Protein Kinase C; D053148:Caspase 3