title: Role of cathepsins D in the midgut of Dysdercus peruvianus.
abstract: Hemipteran ancestors probably lost their digestive serine peptidases on adapting to a plant sap diet. On returning to protein ingestion, these insects start using cathepsin (lysosomal) peptidases as digestive enzymes, from which the less known is cathepsin D. Nine of the ten cathepsin D transcribing genes found in Dysdercus peruvianus midgut are expressed exclusively in this tissue and only DpCatD10 is also expressed in other tissues. The main action of cathepsins D is in the first (V1) (from three, V1-3) midgut regions, where 40% of the total proteolytic activity was assigned to aspartic peptidases with an optimum pH of 3.5. The most expressed cathepsins D were identified in the midgut luminal contents by proteomics. The data indicate that D. peruvianus have kept a lysosomal gene expressed in all tissues and evolved another set of genes with a digestive function restricted to midgut. Digestive cathepsins D apparently complement the action of digestive cathepsin L and they are arguably responsible for the hydrolysis of cysteine peptidase inhibitors known to be present in the cotton seeds eaten by the insect, before they meet cathepsin L.
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil.
authors.forename: André C
authors.initials: AC
authors.lastname: Pimentel
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil.
authors.forename: Felipe J
authors.initials: FJ
authors.lastname: Fuzita
authors.affiliation: Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, 05508-000 São Paulo, Brazil.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Palmisano
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil.
authors.forename: Clélia
authors.initials: C
authors.lastname: Ferreira
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil. Electronic address: warterra@iq.usp.br.
authors.forename: Walter R
authors.initials: WR
authors.lastname: Terra
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002402:Cathepsin D / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D056668:Cathepsin L / Q000037:antagonists & inhibitors; D003198:Computer Simulation; D004064:Digestive System / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D003368:Gossypium / Q000737:chemistry; D020062:Heteroptera / Q000201:enzymology* / Q000235:genetics; D010936:Plant Extracts / Q000494:pharmacology; D059748:Proteolysis; D012639:Seeds / Q000737:chemistry
chemical_list: D010936:Plant Extracts; D056668:Cathepsin L; D002402:Cathepsin D
keywords: Aspartic peptidase; Cathepsin L; Digestion; Hemiptera; Protease