Neuronal specific protein NP185 is enriched in nerve endings: binding characteristics for clathrin light chains, synaptic vesicles, and synaptosomal plasma membrane.
The neuronal specific protein NP185, found associated with brain clathrin-coated vesicles, formed a complex with unphosphorylated, but not with phosphorylated, clathrin light chains. The NP185-clathrin light chain complex was associated with casein kinase II activity, which, in the presence of polylysine, phosphorylated clathrin light chain b but not the NP185. The dissociation of this complex with 50% ethylene glycol pH 11.5 suggests that NP185 binds to hydrophobic domains of clathrin light chains. When NP185 molecules were retained by monoclonal antibody-linked Sepharose beads, they bound synaptic vesicles, decoated vesicles and synaptosomal plasma membrane. Immunohistochemistry on mouse cerebellar tissue sections using 8G8, a monoclonal antibody raised against NP185, showed neuronal specific labeling closely following synaptic distribution. In immunoblots, NP185 shares similar epitopes to those detected in another assembly polypeptide, AP-180, an indication that both proteins are identical. It appears that NP185 plays a specific role in nerve ending functions through its ability to induce clathrin to polymerize into cages, its interaction with synaptic vesicles, with the plasma membrane and with clathrin coat components.
Su
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Department of Pathology, Mount Sinai School of Medicine, New York, NY 10029.
Hanson
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V
Perry
D
D
Puszkin
S
S
D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D000911:Antibodies, Monoclonal; D001921:Brain / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002846:Chromatography, Affinity; D002966:Clathrin / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism* / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008970:Molecular Weight; D034041:Monomeric Clathrin Assembly Proteins; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D013572:Synaptic Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D013574:Synaptosomes / Q000378:metabolism* / Q000648:ultrastructure
D033942:Adaptor Proteins, Vesicular Transport; D000911:Antibodies, Monoclonal; D002966:Clathrin; D046911:Macromolecular Substances; D034041:Monomeric Clathrin Assembly Proteins; D009419:Nerve Tissue Proteins; C439023:clathrin assembly protein AP180