A hemolymph major anionic peptide, HemaP, motivates feeding behavior in the sweetpotato hornworm, Agrius convolvuli.
We recently identified a novel feeding-modulating peptide, hemolymph major anionic peptide (HemaP), designated Bommo-HemaP (B-HemaP), from hemolymph of the silkworm Bombyx mori. B-HemaP has a unique biological activity in modulating the regular frequency of feeding motivation, which is accompanied by increased foraging behaviors. To confirm the conservation of the HemaP-regulated feeding mechanism in lepidopteran species, we purified and sequenced two candidate peptides from the hemolymph of larvae of the sweet potato hornworm Agrius convolvuli. Unlike B. mori, A. convolvuli had two forms of HemaP, which were designated Agrco-HemaP-1 (A-HemaP-1) and Agrco-HemaP-2 (A-HemaP-2). The amino acid sequence of A-HemaP-2 was identical with that of A-HemaP-1, except for O-glycosylation on the fifth amino acid, threonine, within the N-terminal region. The amino acid sequence of A-HemaP-1/A-HemaP-2 had only 32% identity with B-HemaP. Structural analysis revealed that the carbohydrate moiety of A-HemaP-2 was an α-GalNAc residue. Injection of A-HemaP-1, A-HemaP-2 and recombinant A-HemaP-1 (rA-HemaP-1) individually caused a significant increase in foraging behaviors in A. convolvuli larvae, and no significant differences were observed among these three A-HemaPs. The CD spectra of these three A-HemaPs were quite similar, and all had α-helix-rich secondary structures. Although A-HemaP-1 and B-HemaP did not exhibit cross-reactivity at any injection doses examined, HemaP might be a conserved molecule among lepidopteran species that can modulate feeding motivation through the fluctuation of peptide levels in hemolymph.
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan.
Nobukatsu
N
Morooka
Shinji
S
Nagata
Koji
K
Shirai
Kenji
K
Kiguchi
Hiromichi
H
Nagasawa
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002942:Circular Dichroism; D003001:Cloning, Molecular; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D006458:Hemolymph / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D009036:Moths / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D009042:Motivation; D010446:Peptide Fragments / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D019476:Insect Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins