title: Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) open reading frame 4 protein (kaposica) is a functional homolog of complement control proteins.
abstract: The genome analysis of Kaposi's sarcoma-associated herpesvirus (KSHV) has revealed the presence of an open reading frame (ORF 4) with sequence homology to complement control proteins. To assign a function to this protein, we have now expressed this ORF using the Pichia expression system and shown that the purified protein inhibited human complement-mediated lysis of erythrocytes, blocked cell surface deposition of C3b (the proteolytically activated form of C3), and served as a cofactor for factor I-mediated inactivation of complement proteins C3b and C4b (the subunits of C3 convertases). Thus, our data indicate that this KSHV inhibitor of complement activation (kaposica) provides a mechanism by which KSHV can subvert complement attack by the host.
authors.affiliation: National Centre for Cell Science, Pune University Campus, Ganeshkhind, Pune 411007, India.
authors.forename: Jayati
authors.initials: J
authors.lastname: Mullick
authors.forename: John
authors.initials: J
authors.lastname: Bernet
authors.forename: Akhilesh K
authors.initials: AK
authors.lastname: Singh
authors.forename: John D
authors.initials: JD
authors.lastname: Lambris
authors.forename: Arvind
authors.initials: A
authors.lastname: Sahu
mesh_terms: D003001:Cloning, Molecular; D003167:Complement Activation; D003169:Complement Inactivator Proteins / Q000494:pharmacology; D005786:Gene Expression Regulation; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016366:Open Reading Frames; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*
chemical_list: D003169:Complement Inactivator Proteins; D014764:Viral Proteins