P₄₀₀ protein characteristic to Purkinje cells and related proteins in cerebella from neuropathological mutant mice: Autoradiographic study by ¹⁴C-leucine and phosphorylation

P₄₀₀ protein has been found in the cerebellum and localizes to Purkinje cells. It is a glycoprotein and reacts with plant lectins. Autoradiographic patterns of the protein profiles of mutant mice cerebella after intracranial injections of ¹⁴C-leucine were analyzed. P₄₀₀ protein was one of the dominant proteins labeled in the control cerebellum. No incorporation of ¹⁴C-leucine to the position of P₄₀₀ protein was found in the nervous and pcd mutant mice where no Purkinje cells and no P₄₀₀ protein are present. P₄₀₀ protein in weaver cerebellum was labelled more intensely than that in the control. In the staggerer mice, where dendritic arborization of Purkinje cell is poor and no spines are formed on the dendrites, no P₄₀₀ protein was found and no ¹⁴C-leucine incorporation was observed to the position of P₄₀₀ protein, suggesting that staggerer is a mutation where no P₄₀₀ protein accumulated in the fractions being studied. P₄₀₀ protein was phosphorylated independently of the presence of Ca²⁺. Among the proteins of the isolated Purkinje cells, P₄₀₀ protein was one of the major proteins phosphorylated.