Src酪氨酸激酶的自硫代磷酸化活性
Auto-thiophosphorylation activity of Src tyrosine kinase.
作者信息
Cabail M Zulema, Chen Emily I, Koller Antonius, Miller W Todd
机构信息
Department of Physiology and Biophysics, School of Medicine, Stony Brook University, Stony Brook, NY, 11794, USA.
Biological Sciences Department, SUNY College at Old Westbury, Old Westbury, NY, 11568, USA.
出版信息
BMC Biochem. 2016 Jul 7;17(1):13. doi: 10.1186/s12858-016-0071-z.
BACKGROUND
Intermolecular autophosphorylation at Tyr416 is a conserved mechanism of activation among the members of the Src family of nonreceptor tyrosine kinases. Like several other tyrosine kinases, Src can catalyze the thiophosphorylation of peptide and protein substrates using ATPγS as a thiophosphodonor, although the efficiency of the reaction is low.
RESULTS
Here, we have characterized the ability of Src to auto-thiophosphorylate. Auto-thiophosphorylation of Src at Tyr416 in the activation loop proceeds efficiently in the presence of Ni(2+), resulting in kinase activation. Other tyrosine kinases (Ack1, Hck, and IGF1 receptor) also auto-thiophosphorylate in the presence of Ni(2+). Tyr416-thiophosphorylated Src is resistant to dephosphorylation by PTP1B phosphatase.
CONCLUSIONS
Src and other tyrosine kinases catalyze auto-thiophosphorylation in the presence of Ni(2+). Thiophosphorylation of Src occurs at Tyr416 in the activation loop, and results in enhanced kinase activity. Tyr416-thiophosphorylated Src could serve as a stable, persistently-activated mimic of Src.
背景
酪氨酸416位点的分子间自磷酸化是非受体酪氨酸激酶Src家族成员间保守的激活机制。与其他几种酪氨酸激酶一样，Src可以使用ATPγS作为硫代磷酸供体催化肽和蛋白质底物的硫代磷酸化，尽管该反应效率较低。
结果
在此，我们对Src自硫代磷酸化的能力进行了表征。在Ni(2+)存在的情况下，激活环中酪氨酸416位点的Src自硫代磷酸化高效进行，导致激酶激活。其他酪氨酸激酶（Ack1、Hck和IGF1受体）在Ni(2+)存在时也会自硫代磷酸化。酪氨酸416硫代磷酸化的Src对PTP1B磷酸酶的去磷酸化具有抗性。
结论
Src和其他酪氨酸激酶在Ni(2+)存在时催化自硫代磷酸化。Src的硫代磷酸化发生在激活环中的酪氨酸416位点，并导致激酶活性增强。酪氨酸416硫代磷酸化的Src可作为Src的稳定、持续激活模拟物。
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