Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5511103 | Insect Biochemistry and Molecular Biology | 2017 | 10 Pages |
â¢Cathepsins play key roles in the remodeling of the midgut.â¢Cathepsin L functions in the dissociation of the midgut.â¢Caspase-1 is activated by cathepsin L to induce apoptosis in the midgut.â¢Ecdysone is an upstream signal to induce cathepsin L expression.
The larval midgut in holometabolous insects must undergo a remodeling process during metamorphosis to form the pupal-adult midgut. However, the molecular mechanism of larval midgut cell dissociation remains unknown. Here, we show that the expression and activity of Helicoverpa armigera cathepsin L (Har-CatL) are high in the midgut at the mid-late stage of the 6th-instar larvae and are responsive to the upstream hormone ecdysone. Immunocytochemistry shows that signals for Har-CatL-like are localized in midgut cells, and an inhibitor experiment demonstrates that Har-CatL functions in the dissociation of midgut epithelial cells. Mechanistically, Har-CatL can cleave pro-caspase-1 into the mature peptide, thereby increasing the activity of caspase-1, which plays a key role in apoptosis, indicating that Har-CatL is also involved in the apoptosis of midgut cells by activating caspase-1. We believe that this is the first report that Har-CatL regulates the dissociation and apoptosis of the larval midgut epithelium for midgut remodeling.
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