High-resolution proton NMR measures mobile lipids associated with Triton-resistant membrane domains in haematopoietic K562 cells lacking or expressing caveolin-1
High-resolution proton NMR measures mobile lipids associated with Triton-resistant membrane domains in haematopoietic K562 cells lacking or expressing caveolin-1
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DOI：
10.1007/s00249-002-0273-8
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发表时间：
2003-05-01
影响因子：
2
通讯作者：
Sargiacomo, M
中科院分区：
文献类型：
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作者：
Ferretti, A;Knijn, A;Sargiacomo, M
完整肿瘤细胞的高分辨率质子NMR谱通常表现出强烈的信号，由于各向同性移动的脂质（ML）的性质和来源仍然不确定。对完整的野生型和小窝蛋白-1感染的haernatopoietic K562细胞进行的NMR研究表明，在我们的实验条件下，部分ML信号是由于脂质复合物在4 ℃下对Triton X-100中的提取具有抗性。这一证据表明，NMR可见的脂质结构的一部分与Triton抗性膜筏相容，因此在生物药理学上不同于NMR可见的Triton可溶性脂质体。类似于脂筏和小窝，Triton不溶性ML结构域的组织可以通过用β-辛基葡糖苷或甲基-β-环糊精处理而受损。暴露于外源性鞘磷脂酶引起ML NMR可见度增加，表明神经酰胺可能参与ML形成。这些脂质的流动性被发现是温度敏感的，这表明细胞从4摄氏度到25-37摄氏度的转变。这些新的结果在这里讨论的光质膜微区NMR可见ML信号的可能贡献。
High-resolution proton NMR spectra of intact tumour cells generally exhibit intense signals due to isotropically mobile lipids (MLs) of still uncertain nature and origin. NMR studies performed on intact wildtype and caveolin-1-infected haernatopoietic K562 cells showed that, under our experimental conditions, part of the ML signals are due to lipid complexes resistant to extraction in Triton X-100 at 4 degreesC. This evidence suggests that a portion of NMR-visible lipid structures are compatible with Triton-resistant membrane rafts and therefore biophysically distinct from NMR-visible Triton-soluble lipid bodies. Similarly to lipid rafts and caveolae, the organization of the Triton-insoluble ML domains could be compromised by treatment with beta-octylglucoside or methyl-beta-cyclodextrin. Exposure to exogenous sphingomyelinase caused an increase in ML NMR visibility, indicating the possible involvement of ceramides in ML formation. The mobility of these lipids was found to be temperature sensitive, suggesting a transition in cells going from 4 degreesC to 25-37 degreesC. These new results are here discussed in the light of possible contributions of plasma membrane microdomains to NMR-visible ML signals.