Edidin M, Kuo S C, Sheetz M P
Department of Biology, Johns Hopkins University, Baltimore, MD 21218.
Science. 1991 Nov 29;254(5036):1379-82. doi: 10.1126/science.1835798.
Cell membranes often are patchy, composed of lateral domains. These domains may be formed by barriers within or on either side of the membrane bilayer. Major histocompatibility complex (MHC) class 1 molecules that were either transmembrane- (H-2Db) or glycosylphosphatidylinositol (GPI)-anchored (Qa2) were labeled with antibody-coated gold particles and moved across the cell surface with a laser optical tweezers until they encountered a barrier, the barrier-free path length (BFP). At room temperature, the BFPs of Qa2 and H-2Db were 1.7 +/- 0.2 and 0.6 +/- 0.1 (micrometers +/- SEM), respectively. Barriers persisted at 34 degrees C, although the BFP for both MHC molecules was fivefold greater at 34 degrees C than at 23 degrees C. This indicates that barriers to lateral movement are primarily on the cytoplasmic half of the membrane and are dynamic.
细胞膜通常是不连续的，由侧向结构域组成。这些结构域可能由膜双层内部或两侧的屏障形成。用抗体包被的金颗粒标记跨膜的（H-2Db）或糖基磷脂酰肌醇（GPI）锚定的（Qa2）主要组织相容性复合体（MHC）I类分子，并用激光光镊使其在细胞表面移动，直到它们遇到一个屏障，即无障碍路径长度（BFP）。在室温下，Qa2和H-2Db的BFP分别为1.7±0.2和0.6±0.1（微米±标准误）。在34℃时屏障仍然存在，尽管两种MHC分子在34℃时的BFP比在23℃时大五倍。这表明侧向运动的屏障主要位于膜的细胞质一侧，并且是动态的。
