Upregulation of signalase processing and induction of prM-E secretion by the flavivirus NS2B-NS3 protease: Roles of protease components

Vladimir F. Yamshchikov, Dennis W. Trent, Richard W. Compans

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Recently, we have shown that the ability of the flavivirus NS2B-NS3 protease complex to promote efficient signalase processing of the C-prM precursor, as well as secretion of prM and E, does nut appear to depend strictly on cleavage of the precursor at its Lys-Arg-Gly dibasic site by the protease. We suggested that the association of the protease with the precursor via NS2B may be sufficient by itself for the above effects. To study the proposed association in inure detail, we have developed an assay in which processing at the C-prM dibasic cleavage site is abolished by Lys→Gly conversion. We constructed deletion mutants and chimeras of the West Nile (WN) flavivirus NS2B protein and expressed them in the context of {5'- C→NS3243} containing either wild-type C-prM or its cleavage site mutant. All NS2B variants were able to form active protease complexes. Deletion of the carboxy-terminal cluster of hydrophobic amino acids in NS2B had no apparent effect on the formation of prM and prM-E secretion for the cassettes containing either wild-type or mutated C-prM precursor. Deletion of the amino-terminal hydrophobic cluster in NS2B did not affect prM-E secretion for the cassettes with wild-type C-prM but abrogated prM-E secretion for the cassettes with the mutated dibasic cleavage site in C-prM. Similarly, the NS2B-NS3178 protease of Japanese encephalitis (JE) virus, when substituted for the WN virus NS2B-NS3243 protease, was able to promote prM-E secretion for the cassette with the wild-type C-prM precursor but nut with the mutated one. Replacement of the deleted amino-terminal hydrophobic cluster in the WN virus NS2B protein with an analogous JE virus sequence restored the ability of the protease to promote prM-E secretion. On the basis of these observations, roles of individual protease components in upregulation of C- prM signalase processing are discussed.

Original languageEnglish (US)
Pages (from-to)4364-4371
Number of pages8
JournalJournal of Virology
Volume71
Issue number6
StatePublished - Jun 1997

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ASJC Scopus subject areas

  • Immunology

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