Ultrastructural immunocytochemical localization of B-50/GAP43, a protein kinase C substrate, in isolated presynaptic nerve terminals and neuronal growth cones.
Accumulating evidence indicates that the neuron-specific B-50/GAP43, a substrate for protein kinase C, plays a role in neuronal differentiation and neuritogenesis during nervous tissue development and axonal regeneration. An ultrastructural immunocytochemical study on the localization of B-50 in presynaptic terminals (synaptosomes) isolated from the frontal cortex of 6-week-old rats, and in neuronal growth cones, isolated from forebrains of 5-day-old rats, the majority of B-50 is detected at the surrounding neuronal plasma membrane. In both neuronal growth cones and synaptosomes, a relatively small fraction of B-50 in the cytoplasm was not evidently associated with internal membranes. Our results indicate that B-50 is mainly located at the cytoplasmic face of the synaptosomal and neuronal growth cone plasma membrane. The similar B-50 localization in neuronal growth cones and synaptosomes suggests that, both in extending axons and mature synaptic terminals, B-50 may exert identical functions as a protein kinase C substrate at the plasma membrane.
Van Lookeren Campagne
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Division of Molecular Neurobiology Rudolf Magnus Institute, University of Utrecht, The Netherlands.
Oestreicher
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Van Bergen en Henegowen
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Gispen
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D000818:Animals; D001369:Axons / Q000032:analysis* / Q000648:ultrastructure; D002462:Cell Membrane / Q000032:analysis; D005629:Frozen Sections; D019922:GAP-43 Protein; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000032:analysis*; D008854:Microscopy, Electron; D009419:Nerve Tissue Proteins / Q000032:analysis*; D010750:Phosphoproteins / Q000032:analysis*; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000032:analysis* / Q000648:ultrastructure
D019922:GAP-43 Protein; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D011493:Protein Kinase C