Differential effects of filipin and methyl-β-cyclodextrin on B cell receptor signaling
Differential effects of filipin and methyl-β-cyclodextrin on B cell receptor signaling
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DOI：
10.1006/bbrc.2001.5536
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发表时间：
2001-09-14
影响因子：
3.1
通讯作者：
Deans, JP
中科院分区：
文献类型：
--
作者：
Awasthi-Kalia, M;Schnetkamp, PPM;Deans, JP
甲基- β -环糊精和filipin是胆固醇结合试剂，经常互换使用，以研究受体介导的信号转导中脂筏的功能需求。最近，两组使用这些试剂在不同的模型系统中研究脂筏在BCR信号传导中的作用，结果相互矛盾。我们在这里证实，BCR，介导的钙释放被filipin抑制和环糊精增强。然而，filipin的抑制作用不能归因于筏破坏，因为它将筏相关蛋白释放到细胞裂解物的洗涤剂溶相的能力低于环糊精。相比之下，我们发现菲力平能显著抑制筏子相关接头蛋白Cbp/PAG的磷酸化，而环糊精的作用较小。因此，filipin和环糊精通过不同的机制修饰富含胆固醇的微结构域，对受体信号传导产生不同的影响。此外，在最大筏破坏条件下观察到的钙释放增强表明筏具有负调节BCR信号的作用。(C) 2001学术出版社。
Methyl-beta -cyclodextrin and filipin are cholesterol-binding reagents often used interchangeably to investigate functional requirements for lipid rafts in receptor-mediated signal transduction. Recently, contradictory results were reported by two groups using these reagents in different model systems to investigate the role of lipid rafts in BCR signaling. We confirm here that BCR,mediated calcium release is inhibited by filipin and enhanced by cyclodextrin. The inhibitory effect of filipin could not be attributed to raft disruption, however, because its ability to release raft-associated proteins into the detergent-soluble phase of cell lysates was less than that of cyclodextrin. In contrast, we found that filipin profoundly inhibited phosphorylation of the raft-associated adaptor protein Cbp/PAG, whereas the effect of cyclodextrin was minor. Thus, filipin and cyclodextrin modify cholesterol-rich microdomains through different mechanisms with different consequences on receptor signaling. In addition, the enhanced calcium release observed under conditions of maximum raft disruption suggests that rafts have a role in negatively regulating BCR signals. (C) 2001 Academic Press.