Seveau S, Eddy R J, Maxfield F R, Pierini L M
Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10021, USA.
Mol Biol Cell. 2001 Nov;12(11):3550-62. doi: 10.1091/mbc.12.11.3550.
On treatment with chemoattractant, the neutrophil plasma membrane becomes organized into detergent-resistant membrane domains (DRMs), the distribution of which is intimately correlated with cell polarization. Plasma membrane at the front of polarized cells is susceptible to extraction by cold Triton X-100, whereas membrane at the rear is resistant to extraction. After cold Triton X-100 extraction, DRM components, including the transmembrane proteins CD44 and CD43, the GPI-linked CD16, and the lipid analog, DiIC(16), are retained within uropods and cell bodies. Furthermore, CD44 and CD43 interact concomitantly with DRMs and with the F-actin cytoskeleton, suggesting a mechanism for the formation and stabilization of DRMs. By tracking the distribution of DRMs during polarization, we demonstrate that DRMs progress from a uniform distribution in unstimulated cells to small, discrete patches immediately after activation. Within 1 min, DRMs form a large cap comprising the cell body and uropod. This process is dependent on myosin in that an inhibitor of myosin light chain kinase can arrest DRM reorganization and cell polarization. Colabeling DRMs and F-actin revealed a correlation between DRM distribution and F-actin remodeling, suggesting that plasma membrane organization may orient signaling events that control cytoskeletal rearrangements and, consequently, cell polarity.
在用趋化因子处理时,中性粒细胞的质膜会组织形成抗去污剂膜结构域(DRM),其分布与细胞极化密切相关。极化细胞前端的质膜易被冷的Triton X-100提取,而后端的膜则对提取具有抗性。冷的Triton X-100提取后,包括跨膜蛋白CD44和CD43、糖基磷脂酰肌醇连接的CD16以及脂质类似物DiIC(16)在内的DRM成分保留在尾足和细胞体内。此外,CD44和CD43同时与DRM以及F-肌动蛋白细胞骨架相互作用,提示了DRM形成和稳定的机制。通过追踪极化过程中DRM的分布,我们证明DRM从未刺激细胞中的均匀分布发展为激活后立即形成的小的离散斑块。在1分钟内,DRM形成一个包含细胞体和尾足的大帽状结构。这个过程依赖于肌球蛋白,因为肌球蛋白轻链激酶的抑制剂可以阻止DRM重组和细胞极化。对DRM和F-肌动蛋白进行共标记揭示了DRM分布与F-肌动蛋白重塑之间的相关性,提示质膜组织可能使控制细胞骨架重排进而控制细胞极性的信号事件定向。