Raft coalescence and Fc纬RIIA activation upon sphingomyelin clustering induced by lysenin

详细信息	查看全文 | 推荐本文 |

• 作者：Magdalena Kulma ; Katarzyna Kwiatkowska ; Andrzej Sobota ; ^{a.sobota@nencki.gov.pl}
• 关键词：BHK-FcRII ; baby hamster kidney cells stably transfected with Fc纬RIIA ; CDX ; 尾-cyclodextrin ; DRM ; detergent-resistant membrane fragments ; Fc纬RIIA ; Fc纬 receptor IIA ; GPI ; glycosylphosphatidylinositol ; GST ; glutathione-s-transferase ; LDH ; lactate dehydrog
• 刊名：Cellular Signalling
• 出版年：2012
• 期刊代码：42_08986568
• 类别：bio
• 出版时间：August, 2012
• 卷：24
• 期：8
• 页码：1641-1647
• 文件大小：853 K

摘要

Activation of immunoreceptor Fc纬RIIA by cross-linking with antibodies is accompanied by coalescence of sphingolipid/cholesterol-rich membrane rafts leading to the formation of signaling platforms of the receptor. In this report we examined whether clustering of the raft lipid sphingomyelin can reciprocally induce partition of Fc纬RIIA to rafts. To induce sphingomyelin clustering, cells were exposed to non-lytic concentrations of GST-lysenin which specifically recognizes sphingomyelin. The lysenin/sphingomyelin complexes formed microscale assemblies composed of GST-lysenin oligomers engaging sphingomyelin of rafts. Upon sphingomyelin clustering, non-cross-linked Fc纬RIIA associated with raft-derived detergent-resistant membrane fractions as revealed by density gradient centrifugation. Pretreatment of cells with GST-lysenin also increased the size of detergent-insoluble molecular complexes of activated Fc纬RIIA. Sphingomyelin clustering triggered tyrosine phosphorylation of the receptor and its accompanying proteins, Cbl and NTAL, in the absence of receptor ligands and enhanced phosphorylation of these proteins in the ligand presence. These data indicate that clustering of plasma membrane sphingomyelin induces coalescence of rafts and triggers signaling events analogous to those caused by Fc纬RIIA activation.