Influence of the Lipidation Motif on the Partitioning and Association of N-Ras in Model Membrane Subdomains
Influence of the Lipidation Motif on the Partitioning and Association of N-Ras in Model Membrane Subdomains
复制标题
DOI：
10.1021/ja808691r
复制
发表时间：
2009-02-04
影响因子：
15
通讯作者：
Winter, Roland
中科院分区：
文献类型：
--
作者：
Weise, Katrin;Triola, Gemma;Winter, Roland
利用时移敲击模式原子力显微镜的化学、生物学和生物物理相结合的方法，我们研究了不同膜化基序的不同脂化N-RAS蛋白在典型模型RAFT混合物的脂类结构域中的分配。这些结果提供了直接的证据，证明N-RAS优先分配到液体无序的脂类结构域中，而不依赖于脂锚系统。N-RAS蛋白含有至少一个芳胺基团，具有类似的膜分配行为，并表现出蛋白质向液-无序/液-有序相边界区域的扩散，从而降低了结构域间不利的线张力。此外，除了单芳基N-RAS外，强的分子间相互作用促进了在结构域边界的自缔合和纳米团簇的形成，并可能成为缔合过程和纳米团簇的重要载体，这也在活体研究中观察到。GDP负载和GTP负载的N-RAS的定位没有明显变化。相反，非生物的双六角化N-RAS表现出与时间无关的掺入到大块液体无序相以保持其脂链的高构象熵。
In a combined chemical biological and biophysical approach using time-lapse tapping-mode atomic force microscopy, we studied the partitioning of differently lipidated N-Ras proteins with various membranelocalization motifs into lipid domains of canonical model raft mixtures. The results provide direct evidence that partitioning of N-Ras occurs preferentially into liquid-disordered lipid domains, independent of the lipid anchor system. N-Ras proteins bearing at least one famesyl group have a comparable membrane partitioning behavior and show diffusion of the protein into the liquid-disordered/liquid-ordered phase boundary region, thus leading to a decrease of the unfavorable line tension between domains. In addition, except for the monofarnesylated N-Ras, strong intermolecular interactions foster self-association and formation of nanoclusters at the domain boundaries and may serve as an important vehicle for association processes and nanoclustering, which has also been observed in in vivo studies. No significant changes of the localization between GDP- and GTP-loaded N-Ras could be detected. Conversely, the nonbiological dual-hexaclecylated N-Ras exhibits a time-independent incorporation into the bulk liquid-disordered phase to maintain high conformational entropy of its lipid chains.