Proteins identified by mass spectrometry Biological function
Heat shock protein 70 Chaperone: Protein folding and transport; maintain cell homeostasis
subunit 4 delta
Chaperone: assists in the folding of actin, tubulin and other cytosolic proteins
activating factor 3
Haemolymph prophenoloxidase activating factor, induces lethal melanization response by modulating innate immune response
(pro-PO2) (Copper binding
Induces melanization, implicated in the defense against microbes and wounding
PO oxidizes DOPA, and dopamine to melanin to produce quinones which are cytotoxic and facilitate killing of encapsulated pathogens/ parasites
peptide (PP)
Cytokine: involved in defense reaction and growth blocking activity
Spatzle-1 Cytokine: Spätzle acts as the ligand of the Toll receptor to induce transcription of antimicrobial peptides
Notch homolog (Notch) Notch signaling controls numerous cell-fate specification events. Dysregulated Notch signaling causes several diseases. Notch mediates anti-apoptotic activity
DOPA decarboxylase DDC is an intermediate enzyme in the melanization pathway which decarboxylate DOPA to dopamine and is one of the essential enzymes for melanization events
Serpin-4 SERPINs inhibit the serine protease activity, thereby regulating the melanization activity
18 wheeler (18w)/ Toll Toll is a type I transmembrane receptor located on the plasma membrane that controls the dorsal-ventral patterning of the Drosophila embryo and involved in host resistance against fungal and Gram-positive bacterial infections
Chitinase (Chi), transcript variant 3 chitinase play a crucial role in postembryonic development and it is activated after the ecdysone surge during larval–pupal transformation. Chitinase (Endochitinase) catalyzes the hydrolysis of β-(1-4)-glycosidic bonds of chitin polymers to produce chitooligomers
Nedd2-like caspase Caspases induces inflammation as well as apoptosis
Apoptosis-inducing factor (AIF) AIF induces chromatin condensation and DNA fragmentation leading to apoptosis, in the absence of caspase
Autophagy 5-like (Atg5) Atg5 plays a role in autophagosome formation, and is also involved in a pro-apoptotic signalling pathway through cytochrome c release and caspase activation
β –N acetyl glucosaminidase Chitooligomers produced from chitinase are subsequently converted to monomers by exochitinase β-N-acetylglucosaminidases
(membrane trehalase)
The trehalose is converted into glucose by an enzyme, alpha,alpha-trehalase present in insect tissues
Candidate protein components of Toll pathway
Cactus Inhibitor of NF-κB transcription factors
Dorsal NF-κB transcription factor activated during signal transduction in Toll pathway to induce immune reaction
Relish NF-κB transcription factor activated during signal transduction in IMD pathway
Table 1: Biological function of the host-response and immune-response proteins identified by mass spectrometry and three candidate proteins from integument, haemolymph and hemocytes of the final instar larvae of the silkworm, B. mori infested with maggot of E. bombycis.