Ho Jonathan, Theg Steven M
Department of Plant Biology, University of California Davis, Davis, California, United States of America.
PLoS One. 2016 Feb 3;11(2):e0146489. doi: 10.1371/journal.pone.0146489. eCollection 2016.
Stromules are stroma-containing tubules that have been observed to emanate from the main plastidic body in vivo. These structures have been shown to require cytoskeletal components for movement. Though numerous studies have shown a close association with the endoplasmic reticulum, nucleus, mitochondria, and other plastids, the mechanism of formation and their overall function remain unknown. A limiting factor in studying these structures has been the lack of a reconstituted system for in vitro stromule formation. In this study, stromule formation was induced in vitro by adding a plant extract fraction that is greater than 100 kDa to a population of isolated chloroplasts. Kinetic measurements show that stromule formation occurs within ~10 seconds after the addition of the plant extract fraction. Heat inactivation and apyrase treatment reveal that the stromule stimulating compound found in the extract fraction is a protein or protein complex 100 kDa or greater. The formation of the stromules in vitro with isolated chloroplasts and a concentrated fraction of cell extract opens an avenue for the biochemical dissection of this process that has heretofore been studied only in vivo.
基质小管是含有基质的小管，在体内已观察到它们从主要质体主体发出。这些结构已被证明移动需要细胞骨架成分。尽管大量研究表明它们与内质网、细胞核、线粒体和其他质体密切相关，但其形成机制和整体功能仍然未知。研究这些结构的一个限制因素是缺乏用于体外基质小管形成的重组系统。在本研究中，通过向分离的叶绿体群体中添加大于100 kDa的植物提取物组分，在体外诱导了基质小管的形成。动力学测量表明，在添加植物提取物组分后约10秒内发生基质小管的形成。热失活和腺苷三磷酸双磷酸酶处理表明，提取物组分中发现的刺激基质小管形成的化合物是一种100 kDa或更大的蛋白质或蛋白质复合物。利用分离的叶绿体和浓缩的细胞提取物组分在体外形成基质小管，为这一迄今为止仅在体内进行研究的过程的生化剖析开辟了一条途径。
