Protein Kinases in Cerebral Ischemia

Introduction

Protein kinases are key regulators of cell processes. Protein kinases are defined as enzymes that transfer a phosphate group onto an acceptor amino acid in a substrate protein. This process is called phosphorylation and can be reversed by phosphatases, enzymes that remove phosphoryl moieties from target proteins. Protein phosphorylation is an essential mechanism by which intracellular and extracellular signals are transmitted throughout the cell and into the nucleus. It has also been shown that protein phosphorylation regulates various aspects of cellular function, such as division, metabolism, movement, and apoptosis. Because protein kinases play crucial roles in cellular signaling and are highly expressed in the CNS, any disruption of their action can alter cellular function(s) of the neurovascular unit and cause cell death and ultimately, cerebrovascular disease.

The current chapter describes the role of three important protein kinases, i.e., protein kinase A (PKA), protein kinase B (PKB), and protein kinase C (PKC), on the progression of post-ischemic brain injury and their associated cell signaling events. Although there are substantial differences among kinases, their responses to ischemic stress show many similarities.