PREPROPHASE BAND FORMATION INVOLVES ENDOCYTOSIS MEDIATED BY CLATHRIN-COATED PITS

前期带的形成涉及由网格蛋白包被的小凹介导的内吞作用

• 批准号: 7355015
• 负责人: ANDREW L. STAEHELIN
• 金额: $ 0.47万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-26 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7355015
• 关键词: cell membrane; clathrin; endocytosis; plants

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The preprophase band (PPB) is an array of microtubules (MTs) that marks the site on the plant cell plasma membrane where the cell plate will fuse during the final stage of cytokinesis. We have investigated the mechanism of PPB membrane modifications in epidermal cells of cryofixed onion cotyledons by analyzing the endocytic and secretory structures associated with PPB formation in serial thin sections and electron tomograms. The endocytic structures that were quantitatively evaluated in this study included clathrin-coated pits and vesicles, as well as structurally related non-coated vesicles. All of these structures were located within 0.4 ¿m of the plasma membrane and contained characteristic darkly staining cargo molecules. A causal relationship between these structures was demonstrated by short-term treatment with brefeldin A (BFA), a secretory and endocytic pathway inhibitor. Under the conditions used, only a fraction of the Golgi stacks showed BFA-induced structural changes. In contrast, the treatment reduced dark-core endocytic pits by >90%, the number of cortical, clathrin-coated, dark-core vesicles by ~80%, and the number of cortical, non-coated, dark-core vesicles by ~67%. During PPB formation, the number of dark-core, endocytic vesicles adjacent to the forming PPB was 2.6-fold higher than in the cytoplasm underlying the non-PPB regions of the plasma membrane. In contrast, the secretory activities, as monitored via the number of horseshoe-shaped profiles in the plasma membrane, were similar between the two regions. Based on these findings, we propose that the modification of the plasma membrane at the site of the PPB involves removal of selected membrane molecules by clathrin-coated pits and vesicles. Karahara, I., J. Suda, T. Murata, L.A. Staehelin and Y. Mineyuki (2006) Preprophase band formation involves endocytosis mediated by chlathrin-coated pits and vesicles. Submitted to Plant Cell

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。前期带（PPB）是一组微管（MTs），它标志着细胞质膜上细胞板在细胞质分裂的最后阶段融合的位置。通过对低温冷冻洋葱子叶表皮细胞中PPB形成相关的内吞和分泌结构的连续薄片和电子断层扫描，研究了PPB膜修饰的机制。本研究定量评价的内吞结构包括网格蛋白包被的凹坑和囊泡，以及与结构相关的非包被囊泡。所有这些结构都位于距质膜0.4¿m的范围内，并含有典型的深色染色货分子。短期治疗brefeldin A（一种分泌和内吞途径抑制剂）证明了这些结构之间的因果关系。在使用的条件下，只有一小部分高尔基堆显示出bfa引起的结构变化。相比之下，处理使暗核内吞坑减少了约90%，皮质、网格蛋白包被的暗核小泡减少了约80%，皮质、非包被的暗核小泡减少了约67%。在PPB形成过程中，形成PPB附近的暗核内吞囊泡的数量是质膜非PPB区域下面的细胞质的2.6倍。相比之下，通过质膜中马蹄形轮廓的数量来监测的分泌活动在两个区域之间是相似的。基于这些发现，我们提出在PPB位点的质膜的修饰包括通过网格蛋白包覆的凹坑和囊泡去除选定的膜分子。Karahara， I.， J. Suda， T. Murata， L.A. Staehelin和Y. Mineyuki（2006）前期带形成涉及由肉精蛋白包被的坑和囊泡介导的内吞作用。提交给植物细胞