Huge collection of tyrosine kinases, lipid kinases & serine/threonine kinases
Protein phosphorylation is a key aspect in the regulation of a large number of cellular processes including cellular division, metabolism, signal transduction, and many more. There are over 500 kinases encoded by the human genome and it has been estimated that kinases regulate approximately 50% of cellular functions. Kinase is the name given to an enzyme that catalyzes the transfer of a phosphate group from ATP to another molecule. Kinases can be broadly separated by their substrate into protein and lipid kinases with the protein kinases being further classified based on their cellular location and the specific amino acid(s) they phosphorylate.
Cytoplasmic Tyrosine Kinases
Three major classes of non-receptor (cytoplasmic) tyrosine kinases have been identified: Src, Abl and Jak. Many of the non-receptor tyrosine kinases are involved in the mediation of immune and inflammatory responses, and misregulation of these enzymes has been linked to multiple human cancers.
Lipid kinases are one of the most promising new classes of potential drug targets. PI-3 and sphingosine kinases regulate a wide variety of cellular functions, including cell growth, proliferation, differentiation, intracellular trafficking, motility, and survival. As a result, defects in lipid kinase function lead to multiple disease states, including several forms of cancer and diabetes.
Serine/threonine protein kinases phosphorylate the OH group of specific serine or threonine residues. Over 125 different human serine/threonine kinases have been identified. The proteins are involved in the regulation of nearly every cell signaling pathway, including gene expression, growth, proliferation, differentiation, adhesion, motility, and death.