title: Dual function of a bee (Apis cerana) inhibitor cysteine knot peptide that acts as an antifungal peptide and insecticidal venom toxin.
abstract: Inhibitor cysteine knot (ICK) peptides exhibit ion channel blocking, insecticidal, and antimicrobial activities, but currently, no functional roles for bee-derived ICK peptides have been identified. In this study, a bee (Apis cerana) ICK peptide (AcICK) that acts as an antifungal peptide and as an insecticidal venom toxin was identified. AcICK contains an ICK fold that is expressed in the epidermis, fat body, or venom gland and is present as a 6.6-kDa peptide in bee venom. Recombinant AcICK peptide (expressed in baculovirus-infected insect cells) bound directly to Beauveria bassiana and Fusarium graminearum, but not to Escherichia coli or Bacillus thuringiensis. Consistent with these findings, AcICK showed antifungal activity, indicating that AcICK acts as an antifungal peptide. Furthermore, AcICK expression is induced in the fat body and epidermis after injection with B. bassiana. These results provide insight into the role of AcICK during the innate immune response following fungal infection. Additionally, we show that AcICK has insecticidal activity. Our results demonstrate a functional role for AcICK in bees: AcICK acts as an antifungal peptide in innate immune reactions in the body and as an insecticidal toxin in venom. The finding that the AcICK peptide functions with different mechanisms of action in the body and in venom highlights the two-pronged strategy that is possible with the bee ICK peptide.
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea.
authors.forename: Hee Geun
authors.initials: HG
authors.lastname: Park
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea.
authors.forename: Seung Su
authors.initials: SS
authors.lastname: Kyung
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea.
authors.forename: Kwang Sik
authors.initials: KS
authors.lastname: Lee
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea.
authors.forename: Bo Yeon
authors.initials: BY
authors.lastname: Kim
authors.affiliation: Department of Agricultural Biology, National Academy of Agricultural Science, Suwon, Republic of Korea.
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Agricultural Biology, National Academy of Agricultural Science, Suwon, Republic of Korea.
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Yoon
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hyung Wook
authors.initials: HW
authors.lastname: Kwon
authors.affiliation: Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.
authors.forename: Yeon Ho
authors.initials: YH
authors.lastname: Je
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea. Electronic address: brjin@dau.ac.kr.
authors.forename: Byung Rae
authors.initials: BR
authors.lastname: Jin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D001413:Bacillus thuringiensis / Q000254:growth & development; D016367:Baculoviridae / Q000235:genetics; D052982:Beauveria / Q000187:drug effects / Q000254:growth & development; D001514:Bee Venoms / Q000737:chemistry / Q000276:immunology*; D001516:Bees; D004926:Escherichia coli / Q000254:growth & development; D020224:Expressed Sequence Tags; D005216:Fat Body / Q000276:immunology* / Q000382:microbiology; D005670:Fusarium / Q000187:drug effects / Q000254:growth & development; D015870:Gene Expression; D015723:Gene Library; D007306:Insecticides; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D061987:Sf9 Cells
chemical_list: D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D001514:Bee Venoms; D007306:Insecticides; D011994:Recombinant Proteins
keywords: Antifungal peptide; Honeybee; Inhibitor cysteine knot fold; Innate immunity; Insecticidal toxin; Venom