Functions of the Lyn tyrosine kinase in health and disease

To relay information, a cell uses enzymes that put molecular markers on specific proteins so they interact with other proteins or move to specific parts of the cell to have particular functions. A protein called Lyn is one of these enzymes that regulate information transfer within cells to modulate cell growth, survival and movement. Depending on which type of cell and the source of the information input, Lyn can positively or negatively regulate the information output. This ability of Lyn to be able to both turn on and turn off the relay of information inside cells makes it difficult to fully understand its precise function in each specific circumstance. Lyn has important functions for cells involved in blood development, including different while blood cells as well as red blood cells, and in particular for the immune cells that produce antibodies (B-cells), as exemplified by the major B-cell abnormalities that mice with mutations in the Lyn gene display. Certain types of leukaemia and lymphoma appear to have too much Lyn activity that in part causes the characteristics of these diseases, suggesting it may be a good target to develop new anti-leukaemia drugs. Furthermore, some specific types, and even specific subtypes, of solid cancers, e.g. prostate, brain and breast cancer can also have abnormal regulation of Lyn. Consequently, targeting this protein in these cancers could also prove to be beneficial.Both receptor and non-receptor protein tyrosine kinases are essential enzymes in many cellular signaling processes regulating cell growth, differentiation, apoptosis, migration, immune responses, adhesion and metabolism [1]. Members of the Src family of tyrosine kinases are signaling intermediates that can control aspects of these and other biological processes [2,3].Lyn is a member of the Src family of intracellular membrane-associated tyrosine kinases (SFK). Each member has a unique N-terminal region (SH4) encoding a myristoylation site, and may contain one (e.g.