Abstract
This study investigates the exocytic responses of invertebrate hemocytes to pathogen-associated antigens. It demonstrates that a homologue of complement component C3, a key defensive protein of the innate immune system, is expressed by phagocytic hemocytes (non-refractile vacuolated cells) of the tunicate, Styela plicata. C3-like molecules are localized in sub-cellular vesicles and are rapidly exocytosed after stimulation with bacterial, fungal or algal cell surface molecules. Signal transduction analysis indicated that the induced secretion of C3-like molecules is mediated by a G-protein dependent signaling pathway, which modulates tubulin microtubules. All of this evidence indicates that hemocytes can contribute to host defense responses by rapidly exocytosing C3-like proteins at sites of infection.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alkaloids
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Animals
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Benzophenanthridines
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Blotting, Western
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Calcimycin / pharmacology
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Carrageenan / pharmacology
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Cell Survival / drug effects
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Cholera Toxin / pharmacology
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Colchicine / pharmacology
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Colforsin / pharmacology
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Complement C3 / analysis
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Complement C3 / metabolism*
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Cytochalasin D / pharmacology
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Cytoplasmic Vesicles / chemistry
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Enzyme-Linked Immunosorbent Assay
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Exocytosis / drug effects
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Exocytosis / physiology*
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Hemocytes / chemistry
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Hemocytes / physiology*
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Hemocytes / ultrastructure
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Immunohistochemistry
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Kinetics
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Lipopolysaccharides / pharmacology
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Mannans / pharmacology
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Microscopy, Electron
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Phenanthridines / pharmacology
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Staurosporine / pharmacology
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Tetradecanoylphorbol Acetate / pharmacology
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Thapsigargin / pharmacology
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Urochordata / cytology
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Urochordata / immunology
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Urochordata / physiology*
Substances
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Alkaloids
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Benzophenanthridines
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Complement C3
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Lipopolysaccharides
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Mannans
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Phenanthridines
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lipopolysaccharide, E. coli O26-B6
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Colforsin
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Cytochalasin D
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Calcimycin
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Thapsigargin
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Carrageenan
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Cholera Toxin
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chelerythrine
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Staurosporine
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Tetradecanoylphorbol Acetate
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Colchicine