The differential distribution of acetylated and detyrosinated alpha-tubulin in the microtubular cytoskeleton and primary cilia of hyaline cartilage chondrocytes
The differential distribution of acetylated and detyrosinated alpha-tubulin in the microtubular cytoskeleton and primary cilia of hyaline cartilage chondrocytes
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DOI：
10.1046/j.1469-7580.2001.19940393.x
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发表时间：
2001-10-01
影响因子：
2.4
通讯作者：
Ross, JM
中科院分区：
文献类型：
--
作者：
Poole, CA;Zhang, ZJ;Ross, JM
初级纤毛是一种普遍存在的细胞器，功能未知。软骨细胞中初级纤毛的超微结构证据，以及它们与高尔基体的共定位，导致了这些结构在功能上联系的推测。为了探讨这些细胞器之间的关系，我们对鸡胚胸骨软骨细胞的微管细胞骨架进行了分子解剖。厚的冷冻切片用针对乙酰化α -微管蛋白（C3B9）、去酪化ct-微管蛋白（ID5）和总α -微管蛋白（TAT）的抗体进行免疫标记，并用共聚焦高倍成像。激光扫描显微镜。透射电镜证实了软骨细胞初级纤毛的超微结构及其与高尔基体的结构关系。去酪化和乙酰化的α -微管蛋白集中在靠近细胞核的中心粒、中心体和微管组织中心，α -微管蛋白总量分布在细胞质各处。ID5染色原发纤毛的发生率为每个细胞1个，其与C3B9的共定位表明原发纤毛是微管细胞骨架最稳定的特征之一。初生纤毛长度从1 ~ 4毫米不等，有3种向细胞外基质的突起；(1)充分延伸和基体接触，沿长度波动较小；(2)局部延伸与基体接触，具有一定的弯曲挠度；(3)纤毛斜靠在细胞表面，与基质接触最小。超微结构研究发现细胞外胶原纤维与修饰纤毛微管的蛋白质之间存在直接联系，表明透明软骨细胞中存在基质-纤毛-高尔基连续体。这些结果加强了初级纤毛作为“细胞控制论探针”的假设，它能够从细胞外基质中传递环境信息，将这些信息传递给中心体，并调节高尔基衍生的分泌囊泡的胞外分泌。
The primary cilium is a ubiquitous cytoplasmic organelle of unknown function. Ultrastructural evidence of primary cilia in chondrocytes, and their colocalisation with the Golgi apparatus, has led to speculation that these structures are functionally linked. To investigate the relationship between these organelles, we examined the molecular anatomy of the microtubular cytoskeleton in the chondrocytes of chick embryo sterna. Thick cryosections were immunolabelled with antibodies directed against acetylated alpha -tubulin (C3B9), detyrosinated ct-tubulin (ID5) and total alpha -tubulin (TAT), and imaged at high magnification using confocal. laser scanning microscopy. Transmission electron microscopy confirmed the ultrastructure of the chondrocyte primary cilium and its structural relationship to the Golgi apparatus. Detyrosinated and acetylated alpha -tubulins were concentrated in the centrioles, centrosome and microtubule organising centre adjacent to the nucleus, with total alpha -tubulin distributed throughout the cytoplasm. ID5 stained the primary cilium at an incidence of 1 per cell, its colocalisation with C3B9 identifying the primary cilium as one of the most stable features of the microtubular cytoskeleton. Primary cilia varied from 1 to 4 mum in length, and 3 patterns of projection into the extracellular matrix were identified; (1) full extension and matrix contact, with minor undulations along the length; (2) partial extension and matrix contact, with a range of bending deflections; (3) cilium reclined against the cell surface with minimal matrix contact. Ultrastructural studies identified direct connections between extracellular collagen fibres and the proteins which decorate ciliary microtubules, suggesting a matrix-cilium-Golgi continuum in hyaline chondrocytes. These results strengthen the hypothesis that the primary cilium acts as a 'cellular cybernetic probe' capable of transducing environmental information from the extracellular matrix, communicating this information to the centrosome, and regulating the exocytosis of Golgi-derived secretory vesicles.