Proteolytic Activity of 26S Proteasomes Isolated from Muscles of the Tobacco Hornworm, Manduca sexta: Differences between Surviving Muscles and those Undergoing Developmentally Programmed Cell Death
The intersegmental muscles (ISMs) of tobacco hornworm, Manduca sexta are a well-characterised model system for examining the biochemical changes that accompany programmed cell death during development. When the ISMs become committed to die, there are dramatic increases in both the ubiquitin-expression, and ubiquitin-dependent proteolysis. Since the 26S proteasome is responsible for ATP/ubiq-uitin-dependent proteolysis in cells, we examined its enzymatic properties. Specific chymotrypsin-like proteolytic activity of 26S proteasomes isolated from ISM is four times higher than that of surviving flight muscle (FM). However, specific activity does not change between developmental stages within ISM or FM. The difference between proteolytic capacity of the two kinds of muscles is even higher when the ISM become committed to die because 26S proteasome content of ISM increases just before cell death. These observations underline the role of 26S proteasome in programmed cell death.
KeywordsManduca sexta 26S proteasome enzyme activity intersegmental muscle flight muscle
Unable to display preview. Download preview PDF.
- 4.Dawson, S. P., Arnold, J. E., Mayer, N. J., Reynolds, S. E., Billett, M. A., Gordon, C, Colleaux, L., Kloetzel, P. M., Tanaka, K., Mayer, R. J. (1995) Developmental changes of the 26S proteasome in abdominal intersegmental muscles of Manduca sexta during programmed cell death. J. Biol. Chem. 270, 1850–1858.CrossRefGoogle Scholar
- 8.Jones, M. E. E., Haire, M. F., Kloetzel, P.-M., Mykles, D. L., Schwartz, L. M. (1995) Changes in the structure and function of the multicatalytic proteinase (proteasome) during programmed cell death in the intersegmental muscles of the hawkmoth, Manduca sexta. Dev. Biol. 169, 436–447.CrossRefGoogle Scholar
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.