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Tyrosine phosphorylation is the addition of a phosphate (PO43−) group to the amino acid tyrosine on the protein. This transfer of phosphate group from ATP to the amino acid tyrosine on the protein is made possible through the enzyme tyrosine kinase. Tyrosine phosphorylation is considered to be one of the key steps in signal transduction and regulation of enzymatic activity. ==History== In the summer of 1979 during studies of polyomavirus middle T and v-Src associated kinase activities led to the discovery of tyrosine phosphorylation as a new type of protein modification. Following the 1979 discovery that Src is a tyrosine kinase, the number of distinct tyrosine kinases grew rapidly, accelerated by the advent of rapid DNA sequencing technology and PCR. About one year later was discovered an important role for tyrosine phosphorylation in growth factor signaling and proliferation, and by extension in oncogenesis through hijacking of growth factor tyrosine phosphorylation signaling pathways. The most important role played the year 1990 in which was detected Receptor tyrosine kinases (RTK)s initiate intracellular signaling. Phosphotyrosine (P.Tyr) residues on activated RTKs are recognized by a phosphodependent-binding domain, the SH2 domain. The recruitment of SH2 domain proteins to autophosphorylated RTKs at the plasma membrane is essential for initiating and propagating downstream signaling. SH2 domain proteins may have a variety of functions, including adaptor proteins to recruit other signaling proteins, enzymes that act on membrane molecules, such as phospholipases, cytoplasmic tyrosine kinases that relay signals, E3 ubiquitin ligases, and transcription factors. In the year 1995 were found proteins containing a second type of P.Tyr-binding domain, PTB in the RTK signaling. Gradually grow the number of identified tyrosine kinases and receptor tyrosine kinases. In the year 2002 of the 90 human tyrosine kinases 58 are RTKs and opposing the action of the tyrosine kinases are 108 protein phosphatases that can remove phosphate from P.Tyr in proteins. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「tyrosine phosphorylation」の詳細全文を読む スポンサード リンク
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