Specific roles of Src family kinases in inflammatory signaling pathways

起源于高亲和力免疫球蛋白E受体（FcεRI）的初始生化信号被归因于Src家族激酶。为了了解单个激酶驱动信号传导的机制，我们进行了重构实验：RBL2H3细胞中的fc - ri信号首先被膜锚定的功能获得的c端Src激酶抑制，然后用Src家族激酶重建，其c端负调控序列被a-myc表位取代。这些来自Lyn和Fyn的结构体与耐洗涤剂膜（DRMs）相关，它们与静息的FcεRI相互作用，并重建聚集诱导的信号传导，导致钙动员和ERK1和2激活。被排除在DRMs之外的c- src衍生构建体无法与fc - ε ri相互作用并恢复信号传导，而棕榈酰化Cys3的产生使其能够与DRMs和fc - ε ri相互作用并恢复信号传导。从lynn衍生的结构体中删除Src同源3 （SH3）结构域不会改变其转导系列或信号传导的能力。SH2结构域的缺失不影响其与DRMs和fc - ε ri的关联，也不影响聚集诱导fc - ε ri β和γ亚基酪氨酸磷酸化，但它几乎取消了下一步syk的酪氨酸磷酸化及其对fc - ε ri的募集。这些发现表明，Lyn和Fyn可以驱动FcεRI信号，而c-Src不能驱动FcεRI信号，并且与FcεRI的初始相互作用以及信号向分子组装的进展需要n端棕榈酰化和SH2结构域的顺序。

Initial biochemical signaling originating from high-affinity immunoglobulin E receptor (FcεRI) has been ascribed to Src family kinases. To understand the mechanisms by which individual kinases drive the signaling, we conducted reconstitution experiments : FcεRI signaling in RBL2H3 cells was first suppressed by a membrane-anchored, gain-of-function C-terminal Src kinase and then reconstructed with Src family kinases whose C-terminal negative regulatory sequence was replaced with a-myc epitope. Those constructs derived from Lyn and Fyn, which are associated with detergent-resistant membranes (DRMs), physically interacted with resting FcεRI and reconstructed clustering-induced signaling that leads to calcium mobilization and ERK1 and-2 activation. c-Src-derived construct, which was excluded from DRMs, failed to interact with FcεRI and to restore the signaling, whereas creation of palmitoylatable Cys3 enabled it to interact with DRMs and with FcεRI and to restore the signaling. Deletion of Src homology 3 (SH3) domain from the Lyn-derived construct did not alter its ability to transduce the series or signaling. Deletion of SH2 domain did not affect its association with DRMs and with FcεRI nor clustering-induced tyrosine phosphorylation of FcεRI β and γ subunits, but it almost abrogated the next step of tyrosine phosphorylation of syk and its recruitment to FcεRI.These findings suggest that Lyn and Fyn could, but c-Src could not, drive FcεRI signaling and that N-terminal palmitoylation and SH2 domain are required in sequence for the initial interaction with FcεRI and for the signal progression to the molecular assembly.