Faculty of Sciences, BioISI, Biosystems and Integrative Sciences Institute, University of Lisboa, Campo Grande, C8 bdg, 1749-016, Lisbon, Portugal.
Cell Mol Life Sci. 2020 Dec;77(23):4729-4745. doi: 10.1007/s00018-020-03523-w. Epub 2020 Apr 20.
Early eukaryotic cells emerged from the compartmentalization of metabolic processes into specific organelles through the development of an endomembrane system (ES), a precursor of the endoplasmic reticulum (ER), which was essential for their survival. Recently, substantial evidence emerged on how organelles communicate among themselves and with the plasma membrane (PM) through contact sites (CSs). From these studies, the ER-the largest single structure in eukaryotic cells-emerges as a central player communicating with all organelles to coordinate cell functions and respond to external stimuli to maintain cellular homeostasis. Herein we review the functional insights into the ER-CSs with other organelles in a physiological perspective. We hypothesize that, in addition to the primitive role by the ES in the appearance of proto-eukaryotes, its successor-the ER-emerges as the key coordinator of inter-organelle/PM communication. The ER thus appears to be the 'maestro' driving eukaryotic cell evolution by incorporating new functions/organelles, while remaining the real coordinator overarching cellular functions and orchestrating them with the external milieu.
早期真核细胞通过将代谢过程分隔到特定的细胞器中而出现，这是内质网（ER）的前身，这对于它们的生存至关重要。最近，有大量证据表明细胞器如何通过接触位点（CSs）相互以及与质膜（PM）进行通讯。从这些研究中，内质网——真核细胞中最大的单一结构——作为与所有细胞器进行通讯的核心参与者出现，以协调细胞功能并响应外部刺激来维持细胞内稳态。在此，我们从生理角度综述了内质网-CSs 与其他细胞器之间的功能见解。我们假设，除了 ES 在原生生物出现中的原始作用外，它的后继者——内质网——作为细胞器/PM 通讯的关键协调者出现。因此，内质网似乎通过整合新的功能/细胞器成为驱动真核细胞进化的“大师”，同时仍然是全面协调细胞功能的真正协调者，并与外部环境进行协调。
