Rmcystatin3, a cysteine protease inhibitor from Rhipicephalus microplus hemocytes involved in immune response
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Data
2014-11-01
Autores
Lu, Stephen 
Soares, Tatiane Sanches
Lovato, Diogo Ventura
Tanaka, Aparecida Sadae
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Artigo
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The Rhipicephalus microplus tick is responsible for losses in the livestock production estimated in 2 billions USD. Despite its economical importance the knowledge in tick's physiology is sparse. in order to contribute to this scenario we describe the characterization of a cysteine proteinase inhibitor named Rmcystatin-3. Purified recombinant Rmcystatin-3 was able to inhibit cathepsin L (Ki = 2.5 nM), BmCl1 (Ki = 1.8 nM) and cathepsin B (Ki = 136 nM). Western blot and quantitative PCR analysis revealed the presence of Rmcystatin-3 in fat body, salivary gland but mainly in hemocytes. the mRNA levels of Rmcystatin-3 during bacterial challenge are drastically down-regulated. in order to define the Rmcystatin-3 possible role in tick immunity, the cystatin gene was knockdown by RNA interference with and without Escherichia coli infection. Our results showed that the Rmcystatin-3 silenced group was more immune competent to control bacterial infection than the group injected with non-related dsRNA. Taking together, our data strongly suggested an important role of Rmcystatin-3 in tick immunity. (C) 2014 Elsevier B.V. and Societe francaise de biochimie et biologie Moleculaire (SFBBM). All rights reserved.
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Biochimie. Paris: Elsevier France-editions Scientifiques Medicales Elsevier, v. 106C, p. 17-23, 2014.