|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 University of Guelph;
2 Great Lakes Forestry Centre
3 E-mail: pkrell{at}uoguelph.ca
Intracellular processing and trafficking of the baculovirus v-cath expressed cathepsin (V-CATH) which lacks canonical targeting signals, are poorly understood. The cathepsins of Autographa californica multiple nucleopolyhedrovirus (AcMNPV), Choristoneura fumiferana MNPV (CfMNPV) and most other group I NPVs have well-conserved N-termini containing overlapping chymotrypsin cleavage (Y11) and myristoylation motifs (G12) suggestive of proteolytic signal peptide cleavage to generate proV-CATH, and subsequent acylation. To determine proteolytic N-terminal processing of viral cathepsin, HA epitope-coding tags were fused to the 5' and/or 3' ends of AcMNPV and CfMNPV v-cath. Immunoblot analysis suggested a small N-terminal peptide is cleaved for both viruses, indicating that v-cath is expressed as a pre-proenzyme. The two viral homologues undergo similar proteolytic processing, but have different glycosylation or other post-translational modifications. An AcMNPV V-CATH-DsRED fusion protein colocalized to the endoplasmic reticulum with an HDEL-containing GFP. Based on these findings, pre-proV-CATH processing and trafficking mechanisms are postulated.
Received 3 October 2008;
accepted 19 December 2008.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |