The docking protein HEF1 is an apoptotic mediator at focal adhesion sites
The docking protein HEF1 is an apoptotic mediator at focal adhesion sites
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DOI：
10.1128/mcb.20.14.5184-5195.2000
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发表时间：
2000-07-01
影响因子：
5.3
通讯作者：
Golemis, EA
中科院分区：
文献类型：
--
作者：
Law, SF;O'Neill, GM;Golemis, EA
HEF 1（human enhancer of deletenation 1）是一个对接蛋白家族的成员，包括p130（Cas）和Efs。通过在粘着斑位点组装多个蛋白质相互作用，这些蛋白质响应于细胞外基质的整合素受体结合而激活信号级联。HEF 1蛋白受细胞周期调控，全长形式在有丝分裂中在半胱天冬酶共有位点裂解，产生氨基末端55 kDa形式，定位于有丝分裂纺锤体。在HEF 1中的半胱天冬酶裂解位点的鉴定使我们调查HEF 1是否属于在凋亡中裂解的半胱天冬酶底物的选择组，以促进程序性细胞死亡的形态学变化特征。值得注意的是，在MCF-7或HeLa细胞中诱导HEF 1的表达引起广泛的细胞凋亡，如通过多个标准评估的。内源性HEF 1被切割成65-和55-kDa的片段和一个新检测到的28-kDa的形式，响应于诱导细胞凋亡，平行切割的聚（ADP-核糖）聚合酶和黏着斑激酶（FAK）;死亡促进活性的过度表达HEF 1与生产的28-kDa的形式。虽然切割的HEF 1形式的产生是半胱天冬酶依赖性的，但HEF 1形式的积累进一步受到蛋白酶体的调节，因为蛋白酶体抑制剂N-乙酰基-L-亮氨酰-L-亮氨酰-L-正亮氨酰和乳胞素增强了它们的稳定性。最后，HEF 1表达的诱导也增加了Jun N-末端蛋白激酶（JNK）的激活，激活的JNK与HEF 1共定位，暗示这一途径在HEF 1的作用。基于这些结果，我们认为HEF 1及其家族成员沿着FAK的失调可能是粘着斑破坏的信号，并调节细胞凋亡的发生。
HEF1 (human enhancer of filamentation 1) is a member of a docking protein family that includes p130(Cas) and Efs. Through assembly of multiple protein interactions at focal adhesion sites, these proteins activate signaling cascades in response to integrin receptor binding of the extracellular matrix. The HEF1 protein is cell cycle regulated, with full-length forms cleaved in mitosis at a caspase consensus site to generate an aminoterminal 55-kDa form that localizes to the mitotic spindle. The identification of a caspase cleavage site in HEF1 led us to investigate whether HEF1 belongs to a select group of caspase substrates cleaved in apoptosis to promote the morphological changes characteristic of programmed cell death. Significantly, inducing expression of HEF1 in MCF-7 or HeLa cells causes extensive apoptosis, as assessed by multiple criteria. Endogenous HEF1 is cleaved into 65- and 55-kDa fragments and a newly detected 28-kDa form in response to the induction of apoptosis, paralleling cleavage of poly(ADP-ribose) polymerase and focal adhesion kinase (FAK); the death-promoting activity of over-expressed HEF1 is associated with production of the 28-kDa form. While the generation of the cleaved HEF1 forms is caspase dependent, the accumulation of HEF1 forms is further regulated by the proteasome, as the proteasome inhibitors N-acetyl-L-leucinyl-L-leucinyl-L-norleucinyl and lactacystin enhance their stability. Finally, the induction of HEF1 expression also increases Jun N-terminal protein kinase (JNK) activation, and activated JNK colocalizes with HEF1, implicating this pathway in HEF1 action. Based on these results, we propose that dysregulation of HEF1 and its family members along with FAK may signal the destruction of focal adhesion sites and regulate the onset of apoptosis.