Non-receptor tyrosine kinases
non-receptor tyrosine kinases
Non-receptor tyrosine kinases (nRTKs) are cytoplasmic enzymes that are responsible for catalysing the transfer of a phosphate group from a nucleoside triphosphate donor, such as ATP, to tyrosine residues in proteins. Non-receptor tyrosine kinases are a subgroup of protein family tyrosine kinases, enzymes that can transfer the phosphate group from ATP to a tyrosine residue of a protein (phosphorylation). These enzymes regulate many cellular functions by switching on or switching off other enzymes in a cell.  Unlike the receptor tyrosine kinases (RTKs), the second subgroup of tyrosine kinases, the non-receptor tyrosine kinases are cytoplasmic enzymes. Thirty-two non-receptor tyrosine kinases have been identified in human cells ( EC 2.7.10.2 ). Non-receptor tyrosine kinases regulate cell growth, proliferation, differentiation, adhesion, migration and apoptosis, and they are critical components in the regulation of the immune system.