Mitosis-Coupled, Microtubule-Dependent Clustering of Endosomal Vesicles around Centrosomes

Abstract

ABSTRACT. Upon cell division, not only cells themselves but also their organelles undergo drastic shape changes, although the behaviors of organelles other than the Golgi apparatus remain poorly understood. We followed the spatiotemporal changes in the localization of transferrin receptor (TfnR) and other proteins. In early mitotic phases, a population of proteins cycling through the endocytic recycling compartment (ERC) exhibits a distinct spatiotemporal change from that of Golgi proteins. In prophase/prometaphase, when the cell surface-to-volume ratio is reaching its minimum, the ERC proteins are transiently assembled around the centrated centrosome in a microtubule-and dynein-dependent manner, and soon separated polewards into two clusters concomitant with separation of duplicated centrosomes. Electron microscopic analysis revealed that endosomal vesicles containing endocytosed transferrin cluster tightly around centrosomes without fusing with one another. As cytokinesis proceeds, the clusters gradually collapse, and the ERC proteins reassemble around the furrowing equatorial region. FRAP (fluorescence recovery after photobleaching) analyses of EGFP-TfnR-expressing cells revealed minimal membrane exchange between the endosomal clusters and other cellular compartments until anaphase/ telophase, when membrane traffic resumes. Our observations indicate that ERC clustering around centrosomes plays a fundamental role in restricting membrane delivery to the plasma membrane during early mitotic phases, when the cell surface-to-volume ratio reaches its minimum.

Mitotic Golgi translocation of ERK1c is mediated by PI4KIIIβ/14-3-3γ shuttling complex

“…In that study, it was demonstrated that phosphorylation of BARS on Ser147 by PAK1-PAK3 induces BARS interaction with the 14-3-3γ dimer and PI4KIIIβ which, together, serve as a Golgi shuttling complex. However, this mechanism was suggested to act specifically in the vesiculization of the Golgi, which is not very active during mitosis (Takatsu et al, 2013). Here, we demonstrate that the PI4KIIIβ-14-3-3γ complex does affect mitotic Golgi translocation of ERK1c.…”

Rab11 Endosomes Contribute to Mitotic Spindle Organization and Orientation

“…In essence, Rab11-endosomes act as carriers to recruit and organize MT-nucleating material at spindle poles through dynein (Figure 1, 2, 3). We believe that this is particularly significant because previous studies suggested that endosomes, like Golgi complexes and endoplasmic reticulum disperse throughout the cytoplasm during mitosis, and that membrane trafficking is thought to be halted until cytokinesis (Foley and Kapoor, 2013; Yadav and Linstedt, 2011; Chen et al, 2012; Takatsu et al, 2013). Second, when Rab11 is disrupted, the molecular and functional integrity of spindle poles is compromised.…”

ARF1 and ARF4 regulate recycling endosomal morphology and retrograde transport from endosomes to the Golgi apparatus

“…For time-lapse recording, the TfnR-EGFP expressing cells (Kondo et al. , 2012; Takatsu et al. , 2013) were treated with siRNAs as described, incubated in 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid–buffered MEM, placed on a microscope stage prewarmed to 37°C, and then observed using an A1R-MP confocal microscope (Nikon, Melville, NY).…”