Characterization of v-cath, a cathepsin L-like proteinase expressed by the baculovirus Autographa californica multiple nuclear polyhedrosis virus.
Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) contains a 966 bp ORF that encodes a papain type cysteine proteinase with cathepsin L-like characteristics. Using Western blot analysis of infected cell extracts we showed that v-cath proteinase has 35.5 kDa and 32 kDa precursor forms which are processed to a 27.5 kDa mature form in a manner characteristic of papain and cathepsin L. V-cath proteinase activity was greatest under acidic conditions (pH 5.0) and was reduced in the presence of the cysteine proteinase inhibitors, leupeptin and E64. Urea, a known enhancer of cathepsin L activity, also enhanced v-cath proteinase activity. AcMNPV v-cath proteinase was detected post-mortem in tissues of insects infected with wild-type (wt) virus. Insects infected with a v-cath deletion mutant did not become flaccid after death as is normally observed with wt AcMNPV infections. These findings indicate a link between v-cath activity and degradation of host tissues during virus pathogenesis.
Slack
J M
JM
Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada.
Kuzio
J
J
Faulkner
P
P
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D056668:Cathepsin L; D002403:Cathepsins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D003546:Cysteine Endopeptidases; D010450:Endopeptidases; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000201:enzymology* / Q000472:pathogenicity; D018411:Spodoptera
D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D056668:Cathepsin L