scholarly journals Centrosomal ALIX regulates mitotic spindle orientation by modulating astral microtubule dynamics

2018 ◽  
Vol 37 (13) ◽  
Author(s):  
Lene Malerød ◽  
Roland Le Borgne ◽  
Anette Lie‐Jensen ◽  
Åsmund Husabø Eikenes ◽  
Andreas Brech ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Microtubule Dynamics ◽  
Spindle Orientation ◽  
Astral Microtubule

scholarly journals Cdk1-dependent destabilization of long astral microtubules is required for spindle orientation

2020 ◽  
Author(s):  
Divya Singh ◽  
Nadine Schmidt ◽  
Franziska Müller ◽  
Tanja Bange ◽  
Alexander W. Bird
Keyword(s):  
Mitotic Spindle ◽  
Cell Shape ◽  
Microtubule Dynamics ◽  
Spindle Orientation ◽  
Cell Cortex ◽  
Spindle Positioning ◽  
Tissue Organization ◽  
Microtubule Stability ◽  
Astral Microtubule ◽  
Early Mitosis

AbstractThe precise execution of mitotic spindle orientation in response to cell shape cues is important for tissue organization and development. The presence of astral microtubules extending from the centrosome towards the cell cortex is essential for this process, but little is understood about the contribution of astral microtubule dynamics to spindle positioning, or how astral microtubule dynamics are regulated spatiotemporally. The mitotic regulator Cdk1-CyclinB promotes destabilization of centrosomal microtubules and increased microtubule dynamics as cells transition from interphase to mitosis, but how Cdk1 activity specifically modulates astral microtubule stability, and whether it impacts spindle positioning, is unknown. Here we uncover a mechanism revealing that Cdk1 destabilizes astral microtubules to ensure spindle reorientation in response to cell shape. Phosphorylation of the EB1-dependent microtubule plus-end tracking protein GTSE1 by Cdk1 in early mitosis abolishes its interaction with EB1 and recruitment to microtubule plus-ends. Loss of Cdk1 activity, or mutation of phosphorylation sites in GTSE1, induces recruitment of GTSE1 to growing microtubule plus-ends in mitosis. This decreases the catastrophe frequency of astral microtubules, and causes an increase in the number of long astral microtubules reaching the cell cortex, which restrains the ability of cells to reorient spindles along the long cellular axis in early mitosis. Astral microtubules must thus not only be present, but also dynamic to allow the spindle to reorient in response to cell shape, a state achieved by selective destabilization of long astral microtubules via Cdk1.

scholarly journals Microtubule end tethering of a processive kinesin-8 motor Kif18b is required for spindle positioning

2018 ◽  
Vol 217 (7) ◽  
pp. 2403-2416 ◽  
Author(s):  
Toni McHugh ◽  
Agata A. Gluszek ◽  
Julie P.I. Welburn
Keyword(s):  
Cell Division ◽  
Mitotic Spindle ◽  
Essential Role ◽  
Gene Knockout ◽  
Spindle Orientation ◽  
Binding Region ◽  
Spindle Positioning ◽  
Astral Microtubule ◽  
In Vitro Reconstitution

Mitotic spindle positioning specifies the plane of cell division during anaphase. Spindle orientation and positioning are therefore critical to ensure symmetric division in mitosis and asymmetric division during development. The control of astral microtubule length plays an essential role in positioning the spindle. In this study, using gene knockout, we show that the kinesin-8 Kif18b controls microtubule length to center the mitotic spindle at metaphase. Using in vitro reconstitution, we reveal that Kif18b is a highly processive plus end–directed motor that uses a C-terminal nonmotor microtubule-binding region to accumulate at growing microtubule plus ends. This region is regulated by phosphorylation to spatially control Kif18b accumulation at plus ends and is essential for Kif18b-dependent spindle positioning and regulation of microtubule length. Finally, we demonstrate that Kif18b shortens microtubules by increasing the catastrophe rate of dynamic microtubules. Overall, our work reveals that Kif18b uses its motile properties to reach microtubule ends, where it regulates astral microtubule length to ensure spindle centering.

scholarly journals Microtubule end tethering of a processive Kinesin-8 motor Kif18b is required for spindle positioning

2018 ◽  
Author(s):  
Toni McHugh ◽  
Agata Gluszek-Kustusz ◽  
Julie P.I. Welburn
Keyword(s):  
Cell Division ◽  
Mitotic Spindle ◽  
Essential Role ◽  
Gene Knockout ◽  
Integrated Approach ◽  
Spindle Orientation ◽  
Binding Region ◽  
Spindle Positioning ◽  
Symmetric Division ◽  
Astral Microtubule

AbstractMitotic spindle positioning specifies the plane of cell division during anaphase. Spindle orientation and positioning is therefore critical to ensure symmetric division in mitosis and asymmetric division during development. The control of astral microtubule length plays an essential role in positioning the spindle. Here we show using gene knockout that the Kinesin-8 Kif18b controls microtubule length to center the mitotic spindle at metaphase. Using an integrated approach, we reveal that Kif18b is a highly processive plus end-directed motor that uses a C-terminal non-motor microtubule-binding region to accumulate at growing microtubule plus ends. This region is regulated by phosphorylation to spatially control Kif18b accumulation at plus ends and is essential for Kif18b-dependent spindle positioning and regulation of microtubule length. Finally, we demonstrate that Kif18b shortens microtubules by increasing the catastrophe rate of dynamic microtubules. Overall, our work reveals that Kif18b utilizes its motile properties to reach microtubule ends where it regulates astral microtubule length to ensure spindle centering.

The Aurora-A/TPX2 Axis Directs Spindle Orientation by Regulating NuMa and Microtubule Dynamics

2020 ◽  
Author(s):  
Federica Polverino ◽  
Francesco Davide Naso ◽  
Valentina Palmerini ◽  
D. Singh ◽  
Alex Bird ◽  
...  
Keyword(s):  
Microtubule Dynamics ◽  
Spindle Orientation ◽  
Aurora A

scholarly journals Loss of MYO5B expression deregulates late endosome size which hinders mitotic spindle orientation

PLoS Biology ◽  
2019 ◽  
Vol 17 (11) ◽  
pp. e3000531 ◽  
Author(s):  
Changsen Leng ◽  
Arend W. Overeem ◽  
Fernando Cartón-Garcia ◽  
Qinghong Li ◽  
Karin Klappe ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Late Endosome ◽  
Spindle Orientation

scholarly journals NuMA-microtubule interactions are critical for spindle orientation and the morphogenesis of diverse epidermal structures

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Lindsey Seldin ◽  
Andrew Muroyama ◽  
Terry Lechler
Keyword(s):  
Cell Fate ◽  
Mitotic Spindle ◽  
Cell Types ◽  
Epidermal Differentiation ◽  
Spindle Orientation ◽  
Direct Function ◽  
Spindle Positioning ◽  
Adult Mice ◽  
Neonatal Lethality ◽  
The Matrix

Mitotic spindle orientation is used to generate cell fate diversity and drive proper tissue morphogenesis. A complex of NuMA and dynein/dynactin is required for robust spindle orientation in a number of cell types. Previous research proposed that cortical dynein/dynactin was sufficient to generate forces on astral microtubules (MTs) to orient the spindle, with NuMA acting as a passive tether. In this study, we demonstrate that dynein/dynactin is insufficient for spindle orientation establishment in keratinocytes and that NuMA’s MT-binding domain, which targets MT tips, is also required. Loss of NuMA-MT interactions in skin caused defects in spindle orientation and epidermal differentiation, leading to neonatal lethality. In addition, we show that NuMA-MT interactions are also required in adult mice for hair follicle morphogenesis and spindle orientation within the transit-amplifying cells of the matrix. Loss of spindle orientation in matrix cells results in defective differentiation of matrix-derived lineages. Our results reveal an additional and direct function of NuMA during mitotic spindle positioning, as well as a reiterative use of spindle orientation in the skin to build diverse structures.

scholarly journals The mitotic spindle protein CKAP2 potently increases formation and stability of microtubules

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Thomas S McAlear ◽  
Susanne Bechstedt
Keyword(s):  
Cell Division ◽  
Growth Factor ◽  
Mitotic Spindle ◽  
Apparent Rate Constant ◽  
Microtubule Dynamics ◽  
Proliferation Marker ◽  
Microtubule Growth ◽  
Large Rearrangements ◽  
And Function

Cells increase microtubule dynamics to make large rearrangements to their microtubule cytoskeleton during cell division. Changes in microtubule dynamics are essential for the formation and function of the mitotic spindle, and misregulation can lead to aneuploidy and cancer. Using in vitro reconstitution assays we show that the mitotic spindle protein Cytoskeleton-Associated Protein 2 (CKAP2) has a strong effect on nucleation of microtubules by lowering the critical tubulin concentration 100-fold. CKAP2 increases the apparent rate constant ka of microtubule growth by 50-fold and increases microtubule growth rates. In addition, CKAP2 strongly suppresses catastrophes. Our results identify CKAP2 as the most potent microtubule growth factor to date. These finding help explain CKAP2's role as an important spindle protein, proliferation marker, and oncogene.

scholarly journals Warts Phosphorylates Mud to Promote Pins-Mediated Mitotic Spindle Orientation in Drosophila , Independent of Yorkie

2015 ◽  
Vol 25 (21) ◽  
pp. 2751-2762 ◽  
Author(s):  
Evan B. Dewey ◽  
Desiree Sanchez ◽  
Christopher A. Johnston
Keyword(s):  
Mitotic Spindle ◽  
Spindle Orientation

scholarly journals PTEN controls glandular morphogenesis through a juxtamembrane β-Arrestin1/ARHGAP21 scaffolding complex

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Arman Javadi ◽  
Ravi K Deevi ◽  
Emma Evergren ◽  
Elodie Blondel-Tepaz ◽  
George S Baillie ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Molecular Mechanisms ◽  
Regulatory Protein ◽  
Membrane Binding ◽  
Three Dimensional ◽  
Spindle Orientation ◽  
C2 Domain ◽  
Gtpase Activating Protein ◽  
Defective Mutant ◽  
Glandular Morphogenesis

PTEN controls three-dimensional (3D) glandular morphogenesis by coupling juxtamembrane signaling to mitotic spindle machinery. While molecular mechanisms remain unclear, PTEN interacts through its C2 membrane-binding domain with the scaffold protein β-Arrestin1. Because β-Arrestin1 binds and suppresses the Cdc42 GTPase-activating protein ARHGAP21, we hypothesize that PTEN controls Cdc42 -dependent morphogenic processes through a β-Arrestin1-ARHGAP21 complex. Here, we show that PTEN knockdown (KD) impairs β-Arrestin1 membrane localization, β-Arrestin1-ARHGAP21 interactions, Cdc42 activation, mitotic spindle orientation and 3D glandular morphogenesis. Effects of PTEN deficiency were phenocopied by β-Arrestin1 KD or inhibition of β-Arrestin1-ARHGAP21 interactions. Conversely, silencing of ARHGAP21 enhanced Cdc42 activation and rescued aberrant morphogenic processes of PTEN-deficient cultures. Expression of the PTEN C2 domain mimicked effects of full-length PTEN but a membrane-binding defective mutant of the C2 domain abrogated these properties. Our results show that PTEN controls multicellular assembly through a membrane-associated regulatory protein complex composed of β-Arrestin1, ARHGAP21 and Cdc42.

Sign in / Sign up

Export Citation Format

Share Document