Figure. Comparison of the domain organization of viral and cellular MMPs.

The three major MMP domains are represented by rectangles of different colors and the presence of a signal peptide is shown as a white square. For simplification, the presence of a signal peptide was indicated when at least half of the species encoding mmps within a given virus family predicted a signal peptide. The putative MMP sequences in the following viruses do not predict a signal peptide: Iridoviridae: Invertebrate iridescent virus 22 (YP_008357315.1); Hytrosaviridae: Musca domestica salivary gland hypertrophy virus (YP_001883364.1); Entomopoxvirinae: MsEPV179 (NP_048249.1), Mythimna separata entomopoxvirus 'L' (YP_008003705.1); Baculoviridae: Xestia c-nigrum granulovirus (NP_059188.1), Pieris rapae granulovirus (YP_003429361.1), Epinotia aporema granulovirus (YP_006908552.1)

Baculoviruses encode several different kinds of degradative enzymes and protease inhibitors

Both types of genes are uncommon in viruses

Baculovirus degradative enzymes digest host tissues or enhance midgut infection

Baculovirus protease inhibitors block caspase activity and may suppress immune responses