An analysis of postmortem brain samples from 32 alcoholic and nonalcoholic individuals for protein III, a neuronal...

Protein phosphorylation is a primary mechanism of intracellular signal transduction, and abnormalities in protein phosphorylation have been implicated in the pathogenesis of several specific diseases. Protein III is a neuronal phosphoprotein that is associated with synaptic vesicles and is probably involved in the regulation of neurotransmitter release. Analysis of 32 postmortem brains has confirmed our previous report that variant forms of protein III with higher apparent molecular weights are found frequently in the brains of alcoholic individuals but rarely in the brains of nonalcoholic individuals who did not suffer from any other medical or neuropsychiatric disorders. Eight of 14 (57%) brain samples from alcoholic individuals and four of eight (50%) brain samples from suspected alcoholic individuals had variant forms, while none of 10 samples from nonalcoholic individuals had variant forms. Previous data indicate that variant forms of protein III are also associated with other neurodegenerative conditions, including various dementias, and, possibly, normal aging.