A novel type 1 cystatin involved in the regulation of Rhipicephalus microplus midgut cysteine proteases

Publication date: Available online 13 January 2020Source: Ticks and Tick-borne DiseasesAuthor(s): Stephen Lu, Leticia A. da Rocha, Ricardo J.S. Torquato, Itabajara da Silva Vaz Junior, Monica Florin-Christensen, Aparecida S. TanakaAbstractRhipicephalus microplus is a cattle ectoparasite found in tropical and subtropical regions around the world with great impact on livestock production. R. microplus can also harbor pathogens, such as Babesia sp. and Anaplasma sp. which further compromise cattle production. Blood meal acquisition and digestion are key steps for tick development. In ticks, digestion takes place inside midgut cells and is mediated by aspartic and cysteine peptidases and, therefore, regulated by their inhibitors. Cystatins are a family of cysteine peptidases inhibitors found in several organisms and have been associated in ticks with blood acquisition, blood digestion, modulation of host immune response and tick immunity. In this work, we characterized a novel R. microplus type 1 cystatin, named Rmcystatin-1b. The inhibitor transcripts were found to be highly expressed in the midgut of partially and fully engorged females and they appear to be modulated at different days post-detachment. Purified recombinant Rmcystatin-1b displayed inhibitory activity towards typical cysteine peptidases with high affinity. Moreover, rRmcystatin-1b was able to inhibit native R. microplus cysteine peptidases and RNAi-mediated knockdown of the cystatin transcripts resulted in increa...
Source: Ticks and Tick borne Diseases - Category: Zoology Source Type: research