The endosomal system constitutes a key negotiator between the environment of a cell and its internal affairs. Comprised of a complex membranous network, wherein each vesicle can in principle move autonomously throughout the cell, the endosomal system operates as a coherent unit to optimally face external challenges and maintain homeostasis. Our appreciation of how individual endosomes are controlled in time and space to best serve their collective purpose has evolved dramatically in recent years. In light of these efforts, the endoplasmic reticulum (ER) – with its expanse of membranes permeating the cytoplasmic space – has emerged as a potent spatiotemporal organizer of endosome biology. We review the latest advances in our understanding of the mechanisms underpinning endosomal transport and positioning, with emphasis on the contributions from the ER, and offer a perspective on how the interplay between these aspects shapes the architecture and dynamics of the endosomal system and drives its myriad cellular functions.

内体系统构成细胞环境与其内部事务之间的关键谈判者。内体系统由复杂的膜状网络组成，其中每个囊泡原则上可以在整个细胞中自主移动，内体系统作为一个连贯的单元运行，以最佳地应对外部挑战并保持体内平衡。近年来，我们对如何在时间和空间上控制个体内体以最好地达到其共同目的的认识发生了巨大变化。鉴于这些努力，内质网（ER）的膜层广泛地渗透到细胞质空间中，已成为内体生物学的有效时空组织者。我们回顾了我们对内体运输和定位基础机制的理解的最新进展，