title: Localization and function of Rhipicephalus (Boophilus) microplus vitellin-degrading cysteine endopeptidase.
abstract: The tick Rhipicephalus (Boophilus) microplus is an important parasite of cattle in many areas of the tropics. Characterization of molecules involved in mechanisms such as vitellogenesis and embryo development may contribute to a better understanding of this parasite's physiology. The vitellin-degrading cysteine endopeptidase (VTDCE) is the most active enzyme involved in vitellin hydrolysis in R. microplus eggs. Here we show an association between VTDCE and vitellin in an additional site, apart from the active site. Our data also demonstrate cysteine endopeptidase activity in different tissues such as ovary, gut, fat body, salivary gland and female haemolymph, where it is controlled by a physiological inhibitor. In R. microplus female gut, VTDCE is localized in areas of protein synthesis and trafficking with the underlying haemolymph. VTDCE is also localized in the ovary basal region, in vesicle membranes of ovary pedicel cells and in oocyte cytosol. These results suggest that VTDCE plays a role in vitellin digestion during tick development.
authors.affiliation: Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. adriana@cbiot.ufrgs.br
authors.forename: Adriana
authors.initials: A
authors.lastname: Seixas
authors.forename: Andréia B
authors.initials: AB
authors.lastname: Estrela
authors.forename: Juliana C
authors.initials: JC
authors.lastname: Ceolato
authors.forename: Emerson G
authors.initials: EG
authors.lastname: Pontes
authors.forename: Flávio
authors.initials: F
authors.lastname: Lara
authors.forename: Katia C
authors.initials: KC
authors.lastname: Gondim
authors.forename: Carlos
authors.initials: C
authors.lastname: Termignoni
mesh_terms: D000818:Animals; D002417:Cattle; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D005260:Female; D006458:Hemolymph / Q000378:metabolism; D006868:Hydrolysis; D009928:Organ Specificity; D010053:Ovary / Q000378:metabolism; D011480:Protease Inhibitors / Q000378:metabolism; D048494:Rhipicephalus / Q000201:enzymology* / Q000254:growth & development* / Q000502:physiology; D012469:Salivary Glands / Q000378:metabolism; D047048:Vitellins / Q000378:metabolism*
chemical_list: D011480:Protease Inhibitors; D047048:Vitellins; D003546:Cysteine Endopeptidases