Pathway description:
kinase, alternatively known as a phosphotransferase, is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific target molecules (substrates); the process is termed phosphorylation . The largest group of kinases are protein kinases, which act on and modify the activity of specific proteins. kinase are used extensively to transmit signals and control complex processes in cells. Up to 518 different kinases have been identified in humans. Their enormous diversity and role in signaling makes them attractive targets for drug design. Various other kinases act on small molecules (lipids, carbohydrates, amino acids, nucleotides, and more), either for signaling or to prime them for biochemical reactions in metabolism. These are named after their substrates.
Deregulated kinase activity is a frequent cause of disease, particularly cancer, where kinases regulate many aspects that control cell growth, movement and death. Drugs which inhibit specific kinases are being developed to treat several diseases, and some are currently in clinical use
A phosphatase is an enzyme that removes a phosphate group from its substrate by hydrolysing phosphoric acid monoesters into a phosphate ion and a molecule with a free hydroxyl group (see dephosphorylation). This action is directly opposite to that of phosphorylases and kinases, which attach phosphate groups to their substrates by using energetic molecules like ATP. The addition of a phosphate group may activate or de-activate an enzyme (e.g., Kinase signalling pathways ) or enable a protein-protein interaction to occur (e.g., SH3 domains); therefore phosphatases are integral to many signal transduction pathways.
Therefore ,kinase and phosphatases are closely attached to each other in regulating various cellular events, and play an important role in signal transduction,
References:
Ladbury, JE. (2007)Measurement of the formation of complexes in tyrosine kinase-mediated signal transduction, Acta Cryst D,62,pp26
Zhong-Yin Zhang, (2002) PROTEIN TYROSINE PHOSPHATASES: Structure and Function, Substrate Specificity, and Inhibitor Development, Annual Review of Pharmacology and Toxicology 42, pp209
Mumby, MC & Walter, (1993) G. Protein Serine/Threonine Phosphatases: Structure, Regulation, and Functions in Cell Growth Physiological Reviews,73,pp673
