Regenerating peripheral nerves release a diffusable protein kinase

Using [γ³²P]ATP and 1-dimensional electrophoresis this report shows that a protein kinase is released in the culture medium from adult frog sciatic nerves during regeneration in vitro. The kinase, which phosphorylated serine and to some extent threonine residues, was released from non-neuronal cells. It showed an increased activity during the 3rd to 6th day after injury, coinciding with the injury-induced proliferation of non-neuronal cells. When the proliferation was inhibited by a mitotic agent, the activity of the protein kinase was lowered, further linking it to the division of cells.