Jähne Sebastian, Rizzoli Silvio O, Helm Martin S
Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, Humboldtallee 23, 37073 Göttingen, Germany; International Max Planck Research School for Neurosciences, 37077 Göttingen, Germany.
Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, Humboldtallee 23, 37073 Göttingen, Germany.
Exp Cell Res. 2015 Jul 15;335(2):172-9. doi: 10.1016/j.yexcr.2015.04.017. Epub 2015 May 1.
The function of endosomes and of endosome-like structures in the presynaptic compartment is still controversial. This is in part due to the absence of a consensus on definitions and markers for these compartments. Synaptic endosomes are sometimes seen as stable organelles, permanently present in the synapse. Alternatively, they are seen as short-lived intermediates in synaptic vesicle recycling, arising from the endocytosis of large vesicles from the plasma membrane, or from homotypic fusion of small vesicles. In addition, the potential function of the endosome is largely unknown in the synapse. Some groups have proposed that the endosome is involved in the sorting of synaptic vesicle proteins, albeit others have produced data that deny this possibility. In this review, we present the existing evidence for synaptic endosomes, we discuss their potential functions, and we highlight frequent technical pitfalls in the analysis of this elusive compartment. We also sketch a roadmap to definitely determine the role of synaptic endosomes for the synaptic vesicle cycle. Finally, we propose a common definition of synaptic endosome-like structures.
突触前区室中内体及类内体结构的功能仍存在争议。部分原因在于对于这些区室的定义和标记物尚未达成共识。突触内体有时被视为稳定的细胞器，永久存在于突触中。或者，它们被视为突触小泡循环中的短命中间体，由质膜上大囊泡的内吞作用产生，或由小囊泡的同型融合产生。此外，内体在突触中的潜在功能在很大程度上尚不清楚。一些研究小组提出内体参与突触小泡蛋白分选，尽管其他研究小组提供的数据否定了这种可能性。在本综述中，我们展示了关于突触内体的现有证据，讨论了它们的潜在功能，并强调了在分析这个难以捉摸的区室时常见的技术陷阱。我们还勾勒出一个路线图，以明确确定突触内体在突触小泡循环中的作用。最后，我们提出了突触类内体结构的通用定义。
