title: A new subfamily of penaeidin with an additional serine-rich region from kuruma shrimp (Marsupenaeus japonicus) contributes to antimicrobial and phagocytic activities.
abstract: Penaeidins are an important family of antimicrobial peptides (AMPs) in penaeid shrimp. To date, five groups of penaeidins have been identified in penaeid shrimp. All are composed of a proline-rich N-terminus and a C-terminus containing six cysteine residues engaged in three disulfide bridges. In this study, a new type of penaeidin from Marsupenaeus japonicus was identified. The full-length penaeidin contains a unique serine-rich region and a penaeidin domain, which consists of a proline-rich region and a cysteine-rich region. Here, we classify all penaeidins into two subfamilies. All reported penaeidins are in subfamily I, and the new penaeidin identified in M. japonicus is designated as Penaeidin subfamily II (MjPen-II). MjPen-II was expressed in hemocytes, heart, hepatopancreas, gills, stomach and intestine, and was upregulated after bacterial challenge. A liquid bacteriostatic assay showed that MjPen-II had antibacterial activity to some Gram-positive and Gram-negative bacteria. MjPen-II could bind to bacteria by binding to polysaccharides on the surface of bacteria, thus promoting bacterial agglutination. The serine-rich region enhanced the agglutination activity of MjPen-II. The proline-rich domain had a stronger bacterial-binding activity and polysaccharide-binding activity than the cysteine-rich domain. MjPen-II was also found to be involved in the phagocytosis of bacteria and efficiently improved the phagocytosis rate. Therefore, MjPen-II eliminates bacteria through direct bacterial inhibition as well as by promoting phagocytosis in shrimp.
authors: Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong, 250100, China.
authors: Ming-Yu
authors: MY
authors: An
authors: Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong, 250100, China.
authors: Jie
authors: J
authors: Gao
authors: Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong, 250100, China.
authors: Xiao-Fan
authors: XF
authors: Zhao
authors: Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong, 250100, China. Electronic address: jxwang@sdu.edu.cn.
authors: Jin-Xing
authors: JX
authors: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000145:classification / Q000378:metabolism / Q000494:pharmacology*; D001483:Base Sequence; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D007113:Immunity, Innate / Q000276:immunology*; D033561:Penaeidae / Q000201:enzymology / Q000276:immunology* / Q000382:microbiology; D010586:Phagocytes / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D011135:Polysaccharides, Bacterial; D034741:RNA, Small Interfering
keywords: Antibacterial activity; Antimicrobial peptide; Innate immunity; Marsupenaeus japonicus; Penaeidin; Phagocytosis