Cathepsin D-mediated yolk protein degradation is blocked by acid phosphatase inhibitors

Cathepsin D-mediated yolk protein degradation is blocked by acid phosphatase inhibitors

Author Fialho, E. Google Scholar
Nakamura, A. Google Scholar
Juliano, L. Google Scholar
Masuda, H. Google Scholar
Silva-Neto, MAC Google Scholar
Institution Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Federal de São Paulo (UNIFESP)
Abstract Vitellin (VT) is a lipoglycophosphoprotein stored inside the eggs of every oviparous organism during oogenesis. in the blood-sucking bug Rhodnius prolixus, VT is deposited inside growing oocytes together with two acid hydrolases: acid phosphatase (AP) and cathepsin D (CD). Egg fertilization triggers AP activity and VT proteolysis in vivo [Insect Biochem. Mol. Biol. 2002 (32) 847]. Here, we show that CD is the main protease targeting VT proteolysis during egg development. CD activity in total egg homogenates is blocked by the classical aspartyl protease inhibitor, pepstatin A. Surprisingly, AP inhibitors such as NaF, Na+/K+ tartrate, and inorganic phosphate also block VT proteolysis, whereas this effect is not observed when tyrosine phosphatase inhibitors such as vanadate and phenylarsine oxide or an inhibitor of alkaline phosphatases such as levamisole are used in a VT proteolysis assay. NaF concentrations that block isolated AP activity do not affect the activity of partially purified CD. Therefore, a specific repressor of VT proteolysis must be dephosphorylated by AP in vivo. in conclusion, these results demonstrate for the first time that acid hydrolases act cooperatively to promote yolk degradation during egg development in arthropods. (c) 2005 Elsevier Inc. All rights reserved.
Keywords cathepsin D
Rhodnius prolixus
Language English
Date 2005-04-15
Published in Archives of Biochemistry and Biophysics. New York: Elsevier B.V., v. 436, n. 2, p. 246-253, 2005.
ISSN 0003-9861 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 246-253
Access rights Closed access
Type Article
Web of Science ID WOS:000228225500004

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