title: CD63 Promotes Hemocyte-Mediated Phagocytosis in the Clam,Paphia undulata.
abstract: As one of the surface membrane proteins of tetraspanin family, CD63 plays a crucial role in cellular trafficking and endocytosis, which also is associated with activation of a wide variety of immune cells. Here, the homolog of CD63 was characterized from one marine mollusk,Paphia undulata, which is designated as Pu-CD63. The complete cDNA of Pu-CD63 is 1,738 bp in length with an open reading frame (ORF) of 849 bp, encoding a 282 amino acid protein with four putative hydrophobic transmembrane helixes. Bioinformatic analysis revealed that Pu-CD63 contains one putative YXXØ consensus motif of "110-YVII-113" and one N-glycosylation site "155-NGT-157" within the large extracellular loop (LEL) region, supporting its conserved function in plasma membrane and endosomal/lysosomal trafficking. Moreover, temporal expression profile analysis demonstrates a drastic induction in the expression of CD63 in hemocytes after pathogenic challenge with eitherV. parahaemolyticusorV. alginolyticus. By performing dsRNA-mediate RNAi knockdowns of CD63, a dramatic reduction in hemocytes phagocytic activity to pathogenicVibriois recorded by flow cytometry, revealing the definite role of Pu-CD63 in promoting hemocyte-mediated phagocytosis. Therefore, our work has greatly enhanced our understanding about primitive character of innate immunity in marine mollusk.
authors.affiliation: Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China.
authors.forename: Mingjia
authors.identifier: 0000-0002-8798-0691
authors.initials: M
authors.lastname: Yu
authors.affiliation: Engineering Research Center of Marine Biological Resource Comprehensive Utilization, Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, China.
authors.forename: Shanjun
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Immunology and Pathogen Biology, Zunyi Medical College, Zhuhai Campus, Zhuhai 519041, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Immunology and Pathogen Biology, Zunyi Medical College, Zhuhai Campus, Zhuhai 519041, China.
authors.forename: Qiang
authors.identifier: 0000-0002-5966-4122
authors.initials: Q
authors.lastname: Xia
mesh_terms: D000595:Amino Acid Sequence; D000820:Animal Diseases / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D000818:Animals; D001419:Bacteria / Q000276:immunology; D049872:Bivalvia / Q000502:physiology*; D003001:Cloning, Molecular; D015870:Gene Expression; D020868:Gene Silencing; D006434:Hemocytes / Q000276:immunology* / Q000378:metabolism*; D007113:Immunity, Innate; D016366:Open Reading Frames; D010587:Phagocytosis; D000072417:Protein Domains; D034622:RNA Interference; D060149:Tetraspanin 30 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D060149:Tetraspanin 30