Micaroni Massimo, Mironov Alexander A
Department of Molecular Cell Biology; institute for Molecular Bioscience; The University of Queensland; Brisbane, QLD Australia.
Commun Integr Biol. 2010 Nov;3(6):504-7. doi: 10.4161/cib.3.6.13211. Epub 2010 Nov 1.
Mechanisms for intra-Golgi transport remain a hotly debated topic. Recently, we published data illuminating a new aspect involved in intra-Golgi transport, namely a release of free cytosolic Ca(2+) (Ca(2+)) from the lumen of Golgi cisternae that is fundamental for the secretion and the progression of newly synthesized proteins through the Golgi apparatus (GA). This increase in Ca(2+) during the late stage of synchronous intra-Golgi transport stimulates the fusion of membranes containing cargo proteins and Golgi cisternae, allowing the progression of proteins through the GA. Subsequent restoration of the basal Ca(2+) is also important for the delivery of cargo to the proper final destination. Additionally, the secretory pathway Ca(2+)-ATPase Ca(2+) pump (SPCA1) plays an essential role at this stage. The fine regulation of membrane fusion is also important for the formation and the maintenance of the Golgi ribbon and SPCA1, which regulates Ca(2+) levels, can be considered a controller of trafficking. This evidence contradicts a model of intra-Golgi transport in which permanent membrane continuity allows cargo diffusion and progression.
高尔基体内部运输机制仍然是一个备受争议的热门话题。最近，我们发表的数据揭示了高尔基体内部运输涉及的一个新方面，即高尔基体潴泡腔中游离胞质Ca(2+)（Ca(2+)）的释放，这对于新合成蛋白质通过高尔基体（GA）的分泌和进程至关重要。在同步高尔基体内部运输后期，Ca(2+)的这种增加刺激了含有货物蛋白的膜与高尔基体潴泡的融合，使蛋白质能够通过GA进行转运。随后将基础Ca(2+)恢复到正常水平对于将货物运送到合适的最终目的地也很重要。此外，分泌途径Ca(2+)-ATP酶Ca(2+)泵（SPCA1）在此阶段起着至关重要的作用。膜融合的精细调节对于高尔基体带的形成和维持也很重要，而调节Ca(2+)水平的SPCA1可以被视为运输的控制器。这一证据与高尔基体内部运输模型相矛盾，在该模型中，永久的膜连续性允许货物扩散和转运。
