Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany.
Proc Natl Acad Sci U S A. 2010 Dec 21;107(51):22050-4. doi: 10.1073/pnas.1016184107. Epub 2010 Dec 3.
The physical basis for protein partitioning into lipid rafts remains an outstanding question in membrane biology that has previously been addressed only through indirect techniques involving differential solubilization by nonionic detergents. We have used giant plasma membrane vesicles, a plasma membrane model system that phase separates to include an ordered phase enriching for raft constituents, to measure the partitioning of the transmembrane linker for activation of T cells (LAT). LAT enrichment in the raft phase was dependent on palmitoylation at two juxtamembrane cysteines and could be enhanced by oligomerization. This palmitoylation requirement was also shown to regulate raft phase association for the majority of integral raft proteins. Because cysteine palmitoylation is the only lipid modification that has been shown to be reversibly regulated, our data suggest a role for palmitoylation as a dynamic raft targeting mechanism for transmembrane proteins.
蛋白质在脂质筏中的分区的物理基础仍然是膜生物学中的一个悬而未决的问题，以前只能通过涉及非离子去污剂的差异溶解的间接技术来解决。我们使用了巨大的质膜囊泡，这是一种质膜模型系统，会发生相分离，包括富含筏成分的有序相，以测量 T 细胞激活的跨膜接头（LAT）的分区。LAT 在筏相中的富集依赖于两个近膜半胱氨酸的棕榈酰化，并且可以通过寡聚化来增强。这种棕榈酰化要求也被证明可以调节大多数完整筏蛋白的筏相关联。因为半胱氨酸棕榈酰化是唯一被证明可以可逆调节的脂质修饰，所以我们的数据表明棕榈酰化作为跨膜蛋白的动态筏定位机制的作用。
