The role of phosphorylation in the action of nerve growth factor

Although there is a great deal of information available about the biological effects of nerve growth factor, the detailed mechanism(s) by which it works is still not known. Some general outlines, however, are becoming clear. It is known that a number of second messenger systems are recruited and there is evidence that this recruitment has functional consequences. There is also increasingly strong evidence that nerve growth factor causes the activation of parallel pathways of phosphorylative cascades leading to changes in the phosphorylation and, consequently, in the function of key proteins throughout the cell. It can be suggested that changes in the phosphorylation of nuclear proteins initiate the alterations in gene expression known to occur after nerve growth factor treatment, which underlie the dramatic changes in the overall biology of nerve growth factor-responsive cells.