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Various other kinases act on small molecules such as lipids, carbohydrates, amino acids, and nucleotides, either for signaling or to prime them for metabolic pathways. Specific kinases are often named after their substrates. Protein kinases often have multiple substrates, and proteins can serve as substrates for more than one specific kinase.
Above is a ball-and-stick model of the inorganic phosphate molecule (H PO 4 2−).Colour coding: P (orange); O (red); H (white). The chemical activity of a protein kinase involves removing a phosphate group from ATP and covalently attaching it to one of three amino acids that have a free hydroxyl group.
Structure of Aurora A kinase (PDB: 3E5A) with labeled elements of secondary structure. The catalytic subunits of protein kinases are highly conserved, and the structures of over 280 of the approximately 494 kinase domains from 481 human genes have been determined, [8] leading to large screens to develop kinase-specific inhibitors for the treatments of a number of diseases. [9]
Tyrosine kinases belong to a larger class of enzymes known as protein kinases which also attach phosphates to other amino acids such as serine and threonine. Phosphorylation of proteins by kinases is an important mechanism for communicating signals within a cell (signal transduction) and regulating cellular activity, such as cell division.
ATM serine/threonine kinase or Ataxia-telangiectasia mutated, symbol ATM, is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks (canonical pathway), oxidative stress, topoisomerase cleavage complexes, splicing intermediates, R-loops and in some cases by single-strand DNA breaks. [5]
Receptor tyrosine kinases have been shown not only to be key regulators of normal cellular processes but also to have a critical role in the development and progression of many types of cancer. [2] Mutations in receptor tyrosine kinases lead to activation of a series of signalling cascades which have numerous effects on protein expression. [3]
In enzymology, a nucleoside-phosphate kinase (EC 2.7.4.4) is an enzyme that catalyzes the chemical reaction [1]. ATP + nucleoside phosphate ADP + nucleoside diphosphate. Thus, the two substrates of this enzyme are ATP and nucleoside monophosphate, whereas its two products are ADP and nucleoside diphosphate.
The JAK-STAT pathway in cytokine receptor signalling can activate STATs, which can bind to DNA and allow the transcription of genes involved in immune cell division, survival, activation and recruitment. For example, STAT1 can enable the transcription of genes which inhibit cell division and stimulate inflammation. [2]