Senda T, Yoshinaga-Hirabayashi T
Department of Anatomy I, Nagoya University School of Medicine, Japan.
Anat Rec. 1998 Jul;251(3):339-45. doi: 10.1002/(SICI)1097-0185(199807)251:3<339::AID-AR9>3.0.CO;2-Q.
Intracellular membrane-bounded organelles, such as the endoplasmic reticulum, Golgi apparatus, and mitochondrion, possess and maintain their shape and intrinsic relationship due to the nature of their membrane organization. To reveal the membranous attachments that support these shapes and relationships, we examined various kinds of cells by quick-freeze deep-etch electron microscopy. In the cisternae of the endoplasmic reticula, we found intermembrane bridges linking opposite membranes of the cisternae. Membranes of adjoining rough endoplasmic reticulum cisternae were linked by intermembrane bridges crossing a narrow cytoplasmic gap between cisternae. Intermembrane bridges were also found in and between the Golgi cisternae and in nuclear envelopes. Three kinds of intermembrane bridges were found within mitochondria: one linking between outer and inner mitochondrial membranes and the other two spanning the intracristal space and intercristal matrix space. The presence of intermembrane bridges within membrane organelles, except for those between rough endoplasmic reticulum cisternae, was seen in all cell types examined. Intermembrane bridges within membrane organelles provide a structural basis for the membrane organization of the organelles and thus may contribute to the functional integrity of the organelles.
细胞内膜结合细胞器，如内质网、高尔基体和线粒体，由于其膜组织的性质而具有并维持其形状和内在关系。为了揭示支持这些形状和关系的膜附着结构，我们通过快速冷冻深蚀刻电子显微镜检查了各种细胞。在内质网的潴泡中，我们发现了连接潴泡相对膜的膜间桥。相邻粗面内质网潴泡的膜通过跨越潴泡间狭窄细胞质间隙的膜间桥相连。在高尔基体潴泡内和之间以及核膜中也发现了膜间桥。在线粒体内发现了三种膜间桥：一种连接线粒体外膜和内膜，另外两种跨越嵴内空间和嵴间基质空间。在所检查的所有细胞类型中，除了粗面内质网潴泡之间的膜间桥外，膜细胞器内均可见膜间桥。膜细胞器内的膜间桥为细胞器的膜组织提供了结构基础，因此可能有助于细胞器的功能完整性。
