CEA, CNRS, Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, 38000 Grenoble, France.
Moleculaire Biofysica, Zernike Instituut, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Biochem Soc Trans. 2019 Feb 28;47(1):441-448. doi: 10.1042/BST20180026. Epub 2019 Feb 19.
The endosomal sorting complex required for transport-III (ESCRT-III) and VPS4 catalyze a variety of membrane-remodeling processes in eukaryotes and archaea. Common to these processes is the dynamic recruitment of ESCRT-III proteins from the cytosol to the inner face of a membrane neck structure, their activation and filament formation inside or at the membrane neck and the subsequent or concomitant recruitment of the AAA-type ATPase VPS4. The dynamic assembly of ESCRT-III filaments and VPS4 on cellular membranes induces constriction of membrane necks with large diameters such as the cytokinetic midbody and necks with small diameters such as those of intraluminal vesicles or enveloped viruses. The two processes seem to use different sets of ESCRT-III filaments. Constriction is then thought to set the stage for membrane fission. Here, we review recent progress in understanding the structural transitions of ESCRT-III proteins required for filament formation, the functional role of VPS4 in dynamic ESCRT-III assembly and its active role in filament constriction. The recent data will be discussed in the context of different mechanistic models for inside-out membrane fission.
用于运输的内体分选复合物 III（ESCRT-III）和 VPS4 在真核生物和古菌中催化多种膜重塑过程。这些过程的共同点是将 ESCRT-III 蛋白从细胞质动态招募到膜颈结构的内表面，在膜颈内或在膜颈处激活和形成丝状结构，并随后或同时招募 AAA 型 ATP 酶 VPS4。ESCRT-III 丝和 VPS4 在细胞膜上的动态组装诱导大直径膜颈的收缩，例如胞质分裂的中体和小直径的颈，例如腔内囊泡或包膜病毒的颈。这两个过程似乎使用不同的 ESCRT-III 丝集。然后，收缩被认为为膜分裂奠定了基础。在这里，我们回顾了理解丝状形成所需的 ESCRT-III 蛋白结构转变、VPS4 在动态 ESCRT-III 组装中的功能作用及其在丝状收缩中的积极作用的最新进展。将根据不同的内向外膜分裂机制模型讨论最近的数据。
