{Reference Type}: Journal Article {Title}: The role of tyrosine kinases and their substrates in signal transmission of hematopoietic growth factors: a short review. {Author}: Belka C;Brach MA;Herrmann F; {Journal}: Leukemia {Volume}: 9 {Issue}: 5 {Year}: May 1995 {Factor}: 12.883 {Abstract}: Both structure-function analysis of hematopoietic growth factor receptors and identification of novel signal transduction molecules have provided new insights into the processes involved in signal transmission pathways engaged by hematopoietic growth factors. These investigations have pointed to the importance of post-translational modifications of pre-existing proteins, in particular tyrosine phosphorylation, in transmitting signals and thereby linking extracellular signals to the activation of nuclear effector molecules which govern gene expression. These observations not only contribute to our understanding of the pleiotropism and redundancy ascribed to hematopoietic growth factors, but also help to trace some of the molecules conferring signal specificity. It is to be expected that this rapidly evolving research field will provide us with a significant collection of new findings in the near future and that the precise understanding of the processes involved in ligand-binding and signal transmission will also stimulate the development of novel therapeutic drugs affecting these processes. This article gives a short overview on the role of tyrosine kinases and their substrates in signal transmission processes initiated by hematopoietic growth factors.