Chapter 33 Ecto-protein kinases as mediators for the action of secreted ATP in the brain

Abstract

Publisher Summary This chapter reviews the recent studies on the identification, activity, and function of ecto-protein kinases (PKs) in the central nervous system. The finding demonstrates that antibodies directed against substrates of ecto-protein kinase can inhibit their phosphorylation without penetrating cells, and provide important tools for the investigation of the precise role of specific surface protein phosphorylation systems in the regulation of biological functions. Ecto-PKs have been shown to phosphorylate two types of substrates: cell surface proteins and protein components that reside in the extracellular environment. The chapter reveals that the studies of the extracellular phosphorylation of unique proteins on the surface of brain neurons have implicated a specific, developmentally-regulated, ecto-PK activity in neuritogenesis and synaptogenesis. Studies of the ecto-PKC of human platelets revealed that changes in the phosphorylation state of surface proteins can trigger the membrane rearrangements associated with cellular activation. The hypothesis formulated on the basis of all these studies states that alterations in the phosphorylation state of ecto-domains in surface proteins of developing neurons induce conformational changes leading to rearrangements of membrane components that trigger the onset of neuritogenesis and synaptogenesis.