Characterization of Kunitz-type protease inhibitor purified from hemolymph of Galleria mellonella larvae.
We characterized a Kunitz-type protease inhibitor (Gm KTPI) obtained from the hemolymph of Galleria mellonella larvae immunized with Escherichia coli. The structural analysis of the cloned cDNA showed that it consists of 56 residues derived from the precursor of 75 amino acids. The peptide was constitutively produced in the fat bodies, but not in the midgut nor the integument of larvae. In our analysis of stage-dependent expression, its transcript was detected within the midgut, the fat bodies and the integument of the prepupae, which undergo tissue remodeling. The inhibition assays showed that Gm KTPI was capable of inhibiting only the trypsin-like activity of the larval midgut extracts. Furthermore, it was determined that Gm KTPI induced the activation of extracellular signal-regulated kinase (ERK) in the fat bodies and integument cells, and this kinase is known to perform a central role in cell proliferation signaling. Its effect on ERK activation was also verified in a control experiment using a human endothelial cell culture. Collectively, it was suggested that Gm KTPI might be responsible for the protection of other tissues against proteolytic attack by trypsin-like protease(s) from larval midgut during metamorphosis, and might play a role in the proliferation of cells in the fat body and integument.
Lee
Joon Ha
JH
Department of Biotechnology, Hoseo University, Asan-Si, Chungnam, South Korea.
Kim
Chong Han
CH
Shin
Yong Pyo
YP
Park
Ho Jin
HJ
Park
Seungmi
S
Lee
Hwan Myung
HM
Kim
Byung Sam
BS
Lee
In Hee
IH
D000818:Animals; D004847:Epithelial Cells / Q000201:enzymology / Q000276:immunology; D004926:Escherichia coli / Q000276:immunology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005216:Fat Body / Q000201:enzymology / Q000276:immunology; D015870:Gene Expression; D006458:Hemolymph / Q000737:chemistry / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000201:enzymology / Q000276:immunology; D009036:Moths / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D019476:Insect Proteins; D015842:Serine Proteinase Inhibitors; D048049:Extracellular Signal-Regulated MAP Kinases