Abstract
Rabphilin is a synaptic vesicle-associated protein proposed to play a role in regulating neurotransmitter release. Here we report the isolation and identification of a novel protein complex containing rabphilin, annexin A4 and synaptotagmin 1. We show that the rabphilin C2B domain interacts directly with the N-terminus of annexin A4 and mediates the co-complexing of these two proteins in PC12 cells. Analyzing the cellular localisation of these co-complexing proteins we find that annexin A4 is located on synaptic membranes and co-localises with rabphilin at the plasma membrane in PC12 cells. Given that rabphilin and synaptotagmin are synaptic vesicle proteins involved in neurotransmitter release, the identification of this complex suggests that annexin A4 may play a role in synaptic exocytosis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Amino Acid Sequence
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Animals
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Annexin A4 / metabolism*
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Annexin A4 / physiology
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Calcium-Binding Proteins*
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Cells, Cultured
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Exocytosis
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Macromolecular Substances
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Membrane Glycoproteins / metabolism*
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Nerve Tissue Proteins / metabolism*
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Neurons / chemistry
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Neurons / cytology
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PC12 Cells
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Protein Binding
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Protein Interaction Mapping
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Rabphilin-3A
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Rats
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Rats, Sprague-Dawley
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Synaptic Membranes / chemistry
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Synaptic Vesicles / chemistry
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Synaptotagmin I
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Synaptotagmins
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Vesicular Transport Proteins
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rab GTP-Binding Proteins / metabolism*
Substances
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Adaptor Proteins, Signal Transducing
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Annexin A4
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Calcium-Binding Proteins
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Macromolecular Substances
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Membrane Glycoproteins
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Nerve Tissue Proteins
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Synaptotagmin I
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Syt1 protein, rat
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Vesicular Transport Proteins
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Synaptotagmins
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rab GTP-Binding Proteins