EGFR juxtamembrane domain, membranes, and calmodulin: kinetics of their interaction.
EGFR juxtamembrane domain, membranes, and calmodulin: kinetics of their interaction.
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DOI：
10.1016/j.bpj.2009.03.027
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发表时间：
2009-06
影响因子：
3.4
通讯作者：
P. Sengupta;Eran Bosis;E. Nachliel;M. Gutman;Steven O. Smith;G. Mihalyne;I. Zaitseva;S. McLaughlin
中科院分区：
文献类型：
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作者：
P. Sengupta;Eran Bosis;E. Nachliel;M. Gutman;Steven O. Smith;G. Mihalyne;I. Zaitseva;S. McLaughlin
钙/钙调蛋白（Ca/CaM）与表皮生长因子受体（EGFR）的细胞内质膜结构域（JMD）结合。碱性JMD还与质膜内叶中的酸性脂质结合，这种相互作用可能对受体产生额外水平的自抑制。配体与EGFR的结合产生细胞内钙[Ca 2 +]i的快速增加，从而产生Ca/CaM。Ca/CaM如何与质膜竞争JMD？Ca/CaM是否直接将JMD从膜上拉下来，或者Ca/CaM是否仅在JMD从双层自发解离后才与JMD结合？为了回答这个问题，我们研究了钙/钙调素对荧光JMD肽从磷脂囊泡解离速率的影响，通过动力学停流测量。Ca/CaM增加了解离速率：对描述解离的微分方程的分析表明，Ca/CaM必须直接将基本的JMD肽从膜表面拉下来。这些测量导致EGFR活化的详细原子水平机制，其将预先形成的EGFR二聚体/寡聚体的存在与EGFR激酶结构域活化的Kuriyan变构模型相协调。
Calcium/calmodulin (Ca/CaM) binds to the intracellular juxtamembrane domain (JMD) of the epidermal growth factor receptor (EGFR). The basic JMD also binds to acidic lipids in the inner leaflet of the plasma membrane, and this interaction may contribute an extra level of autoinhibition to the receptor. Binding of a ligand to the EGFR produces a rapid increase in intracellular calcium, [Ca2+]i, and thus Ca/CaM. How does Ca/CaM compete with the plasma membrane for the JMD? Does Ca/CaM directly pull the JMD off the membrane or does Ca/CaM only bind to the JMD after it has dissociated spontaneously from the bilayer? To answer this question, we studied the effect of Ca/CaM on the rate of dissociation of fluorescent JMD peptides from phospholipid vesicles by making kinetic stop-flow measurements. Ca/CaM increases the rate of dissociation: an analysis of the differential equations that describe the dissociation shows that Ca/CaM must directly pull the basic JMD peptide off the membrane surface. These measurements lead to a detailed atomic-level mechanism for EGFR activation that reconciles the existence of preformed EGFR dimers/oligomers with the Kuriyan allosteric model for activation of the EGFR kinase domains.