N-linked glycans located in the pro-region of Bombyx mori nucleopolyhedrovirus V-CATH are essential for the proper folding of V-CATH and V-CHIA.
Post-mortem host degradation by infection of Bombyx mori nucleopolyhedrovirus (BmNPV) requires the synergistic activation of two virus-encoded genes, cathepsin (v-cath) and chitinase (v-chiA). Previous studies have suggested that V-CHIA is essential for the proper folding of the nascent V-CATH polypeptide in the endoplasmic reticulum, and that the putative V-CHIA-V-CATH interaction might be mediated by N-linked glycans of V-CATH. Sequence analysis shows that BmNPV V-CATH includes three consensus N-linked glycosylation sites (asparagine 38, 65 and 158). To clarify the role of N-linked glycans of V-CATH in its biological activity, we generated three recombinant BmNPVs expressing mutant V-CATHs, and found that the two residues, asparagine 38 and 65, which are localized in the pro-region of V-CATH, are the glycosylation sites of BmNPV V-CATH. Western blot analysis also showed that removal of N-linked glycans from BmNPV V-CATH resulted in production of the insoluble forms of V-CATH and V-CHIA. These results demonstrate that N-linked glycans located in the pro-region of BmNPV V-CATH are essential for the proper folding of V-CATH and V-CHIA.
Katsuma
Susumu
S
Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan. katsuma@ss.ab.a.u-tokyo.ac.jp
Nakanishi
Tadashi
T
Daimon
Takaaki
T
Shimada
Toru
T
D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D012831:Bombyx / Q000821:virology*; D002403:Cathepsins / Q000235:genetics / Q000378:metabolism*; D002688:Chitinases / Q000378:metabolism*; D004252:DNA Mutational Analysis; D006031:Glycosylation; D020125:Mutation, Missense; D017924:Nucleopolyhedroviruses / Q000502:physiology*; D011134:Polysaccharides; D017510:Protein Folding; D014764:Viral Proteins / Q000378:metabolism*
D011134:Polysaccharides; D014764:Viral Proteins; D002688:Chitinases; D002403:Cathepsins