Presynaptic localization of B-50 phosphoprotein: the (ACTH)-sensitive protein kinase substrate involved in rat brain polyphosphoinositide metabolism.

This study describes the ultrastructural localization in rat hippocampal tissue in situ and in isolated synaptosomes of the brain-specific phosphoprotein B-50, using affinity purified anti-B-50 immunoglobulins (IgGs). Evidence is presented for the presynaptic localization of B-50 in rat brain. Given this specific localization a model is presented outlining the presumed function of the B-50 protein in the membrane and describing possible neuromodulation by adrenocorticotropin hormone (ACTH)-like peptides.