title: Isolation and characterization of the regulatory subunit of cAMP-dependent protein kinase from the filarial parasite Onchocerca volvulus.
abstract: Protein kinases exert major regulatory effects in eukaryotic signaling events. As these proteins play central regulatory and sensory functions they are interesting targets for antiparasitic drug development and serve as vaccine candidates. A cDNA with an open reading frame of 1122 bp coding for the regulatory subunit of the cAMP-dependent protein kinase (Ov-pka-r) of the pathogenic human nematode Onchocerca volvulus has been isolated. The predicted protein displays 84% homology to the corresponding protein of Caenorhabditis elegans and 71% to the human homologue. The O. volvulus protein has unique features, it includes six cysteine residues, as compared to four residues in mammals. Ov-PKA-r was recombinantly expressed as His-tagged protein and under reducing conditions showed a molecular mass of 52 kDa. In sera from O. volvulus patients IgG antibodies were found that strongly reacted with the recombinant Ov-PKA-r. Using rabbit antisera raised against the recombinant protein for immunohistology allowed the localization of the native Ov-PKA-r within the nervous system and sensory organs of adult O. volvulus worms and of microfilariae. The predominant expression in the nervous system and sensory organs as well as the unique structural features identify this signaling molecule of O. volvulus as a new and interesting target for drug or vaccine development.
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, D-20359 Hamburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Fischer
authors.forename: Sylvain
authors.initials: S
authors.lastname: Djoha
authors.forename: Dietrich W
authors.initials: DW
authors.lastname: Büttner
authors.forename: Peter F
authors.initials: PF
authors.lastname: Zipfel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D003429:Cross Reactions; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D005786:Gene Expression Regulation; D015801:Helminth Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D051379:Mice; D008842:Microfilariae / Q000276:immunology / Q000648:ultrastructure; D008969:Molecular Sequence Data; D017181:Onchocerca volvulus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D009855:Onchocerciasis / Q000276:immunology / Q000473:pathology; D021122:Protein Subunits; D051381:Rats; D011994:Recombinant Proteins / Q000032:analysis / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D015801:Helminth Proteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D017868:Cyclic AMP-Dependent Protein Kinases