Staurosporines Disrupt Phosphatidylserine Trafficking and Mislocalize Ras Proteins
Staurosporines Disrupt Phosphatidylserine Trafficking and Mislocalize Ras Proteins
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DOI：
10.1074/jbc.m112.424457
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发表时间：
2012-12-21
影响因子：
4.8
通讯作者：
Hancock, John F.
中科院分区：
文献类型：
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作者：
Cho, Kwang-jin;Park, Jin-Hee;Hancock, John F.
致癌突变体Ras在人类癌症中频繁表达，但尚未开发出抗Ras药物。由于膜缔合对于Ras生物活性是必不可少的，因此我们开发了Ras质膜定位抑制剂的高含量测定。我们发现，星形孢菌素和类似物通过阻断磷脂酰丝氨酸的内体再循环，导致磷脂酰丝氨酸从质膜到内膜的再分布，有效地抑制Ras质膜结合。星形孢菌素对K-Ras比H-Ras更有活性。K-Ras被置换到内体并经历不依赖于蛋白酶体的降解，而H-Ras重新分布到高尔基体并且不被降解。质膜上的K-Ras纳米簇也被抑制。Ras错误定位与蛋白激酶C抑制或诱导细胞凋亡无关。星形孢菌素选择性地消除K-Ras信号传导和K-Ras转化细胞的增殖。这些结果确定星形孢菌素作为磷脂酰丝氨酸运输的新型抑制剂，产生对磷脂酰丝氨酸和静电在Ras质膜靶向中的作用的新见解，并验证抗Ras治疗剂的新靶点。
Oncogenic mutant Ras is frequently expressed in human cancers, but no anti-Ras drugs have been developed. Since membrane association is essential for Ras biological activity, we developed a high content assay for inhibitors of Ras plasma membrane localization. We discovered that staurosporine and analogs potently inhibit Ras plasma membrane binding by blocking endosomal recycling of phosphatidylserine, resulting in redistribution of phosphatidylserine from plasma membrane to endomembrane. Staurosporines are more active against K-Ras than H-Ras. K-Ras is displaced to endosomes and undergoes proteasomal-independent degradation, whereas H-Ras redistributes to the Golgi and is not degraded. K-Ras nanoclustering on the plasma membrane is also inhibited. Ras mislocalization does not correlate with protein kinase C inhibition or induction of apoptosis. Staurosporines selectively abrogate K-Ras signaling and proliferation of K-Ras-transformed cells. These results identify staurosporines as novel inhibitors of phosphatidylserine trafficking, yield new insights into the role of phosphatidylserine and electrostatics in Ras plasma membrane targeting, and validate a new target for anti-Ras therapeutics.