Inorganic polyphosphate inhibits an aspartic protease-like activity in the eggs of rhodnius prolixus (Stahl) and impairs yolk mobilization in vitro
| Autor: | Gomes, Fabio Mendonça, Santos, Danielle Maria Perpétua de Oliveira, Maia, Lucimar Soares Motta, Ramos, Isabela Barbosa, Miranda, Kildare Rocha de, Machado, Ednildo de Alcântara |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Zdroj: | Repositório Institucional do INMETRO Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO) instacron:INMETRO |
| Popis: | Submitted by Lívia Oliveira (livia.oliveira2@hotmail.com) on 2012-06-20T12:41:07Z No. of bitstreams: 1 Journal of Cellular Physiology,v.222,n.3,p.606-611,2010.pdf: 165517 bytes, checksum: 1fa03398dbb94c5f3b9d1a6f5f5c01bb (MD5) Approved for entry into archive by Regina Mello(mrmello@inmetro.gov.br) on 2012-06-20T12:51:30Z (GMT) No. of bitstreams: 1 Journal of Cellular Physiology,v.222,n.3,p.606-611,2010.pdf: 165517 bytes, checksum: 1fa03398dbb94c5f3b9d1a6f5f5c01bb (MD5) Made available in DSpace on 2012-06-20T12:51:30Z (GMT). No. of bitstreams: 1 Journal of Cellular Physiology,v.222,n.3,p.606-611,2010.pdf: 165517 bytes, checksum: 1fa03398dbb94c5f3b9d1a6f5f5c01bb (MD5) Previous issue date: 2010 Inorganic polyphosphate (poly P) is a polymer of phosphate residues that has been shown to act as modulator of some vertebrate cathepsins. In the egg yolk granules of Rhodnius prolixus, a cathepsinDis the main protease involved in yolk mobilization and is dependent on an activation by acid phosphatases. In this study, we showed a possible role of poly P stored inside yolk granules on the inhibition of cathepsinDand arrest of yolk mobilization during early embryogenesis of these insects. Enzymatic assays detected poly P stores inside the eggs of R. prolixus. We observed that micromolar poly P concentrations inhibited cathepsin D proteolytic activity using both synthetic peptides and homogenates of egg yolk as substrates. Poly P was a substrate for Rhodnius acid phosphatase and also a strong competitive inhibitor of a pNPPase activity. Fusion events have been suggested as important steps towards acid phosphatase transport to yolk granules. Weobserved that poly P levels in those compartments were reduced after in vitro fusion assays and that the remaining poly P did not have the same cathepsinDinhibition activity after fusion. Our results are consistent with the hypothesis that poly P is a cathepsinDinhibitor and a substrate for acid phosphatase inside yolk granules. It is possible that, once activated, acid phosphatase might degrade poly P, allowing cathepsin D to initiate yolk proteolysis. We, therefore, suggest that degradation of poly P might represent a new step toward yolk mobilization during embryogenesis of R. prolixus. 6 p. : il. |
| Databáze: | OpenAIRE |
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