Date Published: April 15, 2019
Publisher: Public Library of Science
Author(s): Kati Tormanen, Celine Ton, Barbara M. Waring, Kevin Wang, Christine Sütterlin, Claude Prigent.
The close physical proximity between the Golgi and the centrosome is a unique feature of mammalian cells that has baffled scientists for years. Several knockdown and overexpression studies have linked the spatial relationship between these two organelles to the control of directional protein transport, directional migration, ciliogenesis and mitotic entry. However, most of these conditions have not only separated these two organelles, but also caused extensive fragmentation of the Golgi, making it difficult to dissect the specific contribution of Golgi-centrosome proximity. In this study, we present our results with stable retinal pigment epithelial (RPE-1) cell lines in which GM130 was knocked out using a CRISPR/Cas9 approach. While Golgi and centrosome organization appeared mostly intact in cells lacking GM130, there was a clear separation of these organelles from each other. We show that GM130 may control Golgi-centrosome proximity by anchoring AKAP450 to the Golgi. We also provide evidence that the physical proximity between these two organelles is dispensable for protein transport, cell migration, and ciliogenesis. These results suggest that Golgi-centrosome proximity per se is not necessary for the normal function of RPE-1 cells.
The close physical proximity between the Golgi and the centrosome is a typical feature of mammalian cells. In these cells, Golgi membranes are organized as an interconnected ribbon in the perinuclear region of a cell, adjacent to the centrosome, the major microtubule organizing center. This proximity is unique to mammalian cells and not found in yeast, plant or fly cells [1,2]. The molecular mechanisms that establish and maintain Golgi-centrosome proximity and its functional significance remain incompletely understood.
This study aimed at understanding the role of Golgi-centrosome proximity in various cellular processes. Although not present in lower eukaryotes, the unique relationship between these two organelles is a conserved and striking feature of mammalian cells [23,24]. Its functional significance is incompletely understood, mainly because only few experimental manipulations have separated Golgi and centrosome without affecting either Golgi or centrosome organization and function. Here, we present our results with two RPE-1 cell lines in which GM130 was removed by CRISPR-Cas9 and in which the physical proximity between Golgi and centrosome was disrupted.