Abstract
Synaptotagmins bind clathrin AP-2 with high affinity via their second C(2) domain, which indicates they are involved in coated pit function. We now report that expression of synaptotagmins lacking either the second C(2) domain or the entire cytoplasmic region potently inhibit endocytosis. Inhibition was dependent on two intramembrane cysteine residues that were found to be essential for synaptotagmin oligomerization. Cells expressing the wild-type, but not the mutant, truncated synaptotagmin fragment had a reduced number of clathrin-coated pits. These results suggest that the formation of synaptotagmin multimers is an important step in the regulation of coated pit assembly.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Protein Complex alpha Subunits
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Adaptor Proteins, Vesicular Transport
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Calcium-Binding Proteins*
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Cell Line
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Coated Pits, Cell-Membrane / metabolism*
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Coated Pits, Cell-Membrane / physiology
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Coated Pits, Cell-Membrane / ultrastructure
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Cysteine / chemistry
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Cysteine / genetics
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Electrophoresis, Polyacrylamide Gel
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Endocytosis
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Fluorescent Antibody Technique
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Genes, Dominant
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Genetic Vectors
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HeLa Cells
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Humans
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Immunohistochemistry
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Membrane Glycoproteins / genetics
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Membrane Glycoproteins / metabolism*
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Membrane Glycoproteins / physiology*
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Membrane Proteins / chemistry
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Models, Genetic
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Mutagenesis, Site-Directed
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism*
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Nerve Tissue Proteins / physiology*
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Plasmids / metabolism
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Protein Structure, Tertiary
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Proto-Oncogene Proteins c-myc / metabolism
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Recombinant Proteins / metabolism
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Synaptotagmins
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Transfection
Substances
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Adaptor Protein Complex alpha Subunits
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Adaptor Proteins, Vesicular Transport
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Calcium-Binding Proteins
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Membrane Glycoproteins
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Membrane Proteins
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Nerve Tissue Proteins
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Proto-Oncogene Proteins c-myc
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Recombinant Proteins
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Synaptotagmins
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Cysteine