Dynamic steps in receptor tyrosine kinase mediated activation of class IA phosphoinositide 3-kinases (PI3K) captured by H/D exchange (HDX-MS).
Dynamic steps in receptor tyrosine kinase mediated activation of class IA phosphoinositide 3-kinases (PI3K) captured by H/D exchange (HDX-MS).
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DOI：
10.1016/j.jbior.2012.09.005
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发表时间：
2013-01
影响因子：
--
通讯作者：
Williams, Roger L
中科院分区：
文献类型：
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作者：
Burke, John E;Williams, Roger L
所有IA类磷酸肌醇3-激酶（PI 3 KS）的催化亚基都与相同的p85相关亚基结合，并磷酸化PIP 2产生PIP 3，但它们在参与的信号通路中可能存在很大差异。p85亚基与p110催化亚基的结合是组成性的，这抑制了活性，但一些抑制性接触是可逆的，并受到调节。与含磷酸酪氨酸的肽（RTK-pY）的相互作用释放这些抑制性接触的子集。氢/氘交换质谱（HDX-MS）提供了每种同种型特有的动态相互作用图。RTK-pY结合暴露了所有IA类酶的p110螺旋结构域（由于nSH 2接触的释放），并暴露了p110β和p110δ激酶结构域的C端半段（由于cSH 2接触的释放）。与此一致，我们的体外试验表明，所有IA类亚型均受到nSH 2的抑制，但只有p110β和p110δ受到cSH 2的抑制。虽然C2/iSH 2抑制性接触存在于所有亚型中，但HDX表明p110β最容易释放这种接触。不同p110同工酶与p85亚基的独特动态关系可能有助于PI 3 K特异性抑制剂的新策略。
The catalytic subunits of all class IA phosphoinositide 3-kinases (PI3Ks) associate with identical p85-related subunits and phosphorylate PIP2 yielding PIP3, but they can vary greatly in the signaling pathways in which they participate. The binding of the p85 subunit to the p110 catalytic subunits is constitutive, and this inhibits activity, but some of the inhibitory contacts are reversible and subject to regulation. Interaction with phosphotyrosine-containing peptides (RTK-pY) releases a subset of these inhibitory contacts. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) provides a map of the dynamic interactions unique to each of the isotypes. RTK-pY binding exposes the p110 helical domains for all class IA enzymes (due to release of the nSH2 contact) and exposes the C-lobe of the kinase domains of p110β and p110δ (resulting from release of the cSH2 contact). Consistent with this, our in vitro assays show that all class IA isoforms are inhibited by the nSH2, but only p110β and p110δ are inhibited by the cSH2. While a C2/iSH2 inhibitory contact exists in all isoforms, HDX indicates that p110β releases this contact most readily. The unique dynamic relationships of the different p110 isozymes to the p85 subunit may facilitate new strategies for specific inhibitors of the PI3Ks.