Kamata Kotoe, Manno Sumie, Ozaki Makoto, Takakuwa Yuichi
Department of Biochemistry, Tokyo Women's Medical University, Tokyo, Japan.
Am J Hematol. 2008 May;83(5):371-5. doi: 10.1002/ajh.21126.
Membrane microdomains enriched in cholesterol and sphingolipids and containing specific membrane proteins are designated as lipid rafts. Lipid rafts have been implicated in cell signaling pathways in various cell types. Heterotrimeric guanine nucleotide-binding protein (Gsalpha) has been shown to be a raft component of erythrocytes and has been implicated in cell signaling. Rafts are isolated as detergent-resistant microdomains (DRMs) for biochemical analysis. Cholesterol depletion is widely used to disrupt raft structures to study their function in biological membranes. In the present study, we developed an alternate strategy for disrupting raft structures without altering membrane cholesterol content. Lidocaine hydrochloride, an amphipathic local anesthetic, is shown to reversibly disrupt rafts in erythrocyte membranes and alter the Gsalpha dependent signal transduction pathway. These findings provide evidence for the presence of rafts while maintaining normal cholesterol content in erythrocyte membranes and confirm a role for raft-associated Gsalpha in signal transduction in erythrocytes.
富含胆固醇和鞘脂并包含特定膜蛋白的膜微区被称为脂筏。脂筏已被证明参与多种细胞类型的细胞信号通路。异源三聚体鸟嘌呤核苷酸结合蛋白（Gsα）已被证明是红细胞的一种脂筏成分，并与细胞信号传导有关。脂筏被分离为耐去污剂微区（DRM）用于生化分析。胆固醇耗竭被广泛用于破坏脂筏结构以研究其在生物膜中的功能。在本研究中，我们开发了一种在不改变膜胆固醇含量的情况下破坏脂筏结构的替代策略。盐酸利多卡因，一种两亲性局部麻醉剂，被证明可可逆地破坏红细胞膜中的脂筏并改变Gsα依赖的信号转导途径。这些发现为红细胞膜中存在脂筏同时保持正常胆固醇含量提供了证据，并证实了与脂筏相关的Gsα在红细胞信号转导中的作用。
