Menu

Close

Spatiotemporally controlled Myosin relocalization and internal pressure cause biased cortical extension to generate sibling cell size asymmetry

Tri Thanh Pham, Arnaud Monnard, Jonne Helenius, Erik Lund, Nicole Lee, Daniel Mueller, Clemens Cabernard

Preprint posted on May 01, 2018 https://www.biorxiv.org/content/early/2018/05/01/311852

The right cell at the right size: how myosin-dependent tension and hydrostatic pressure coordinate to achieve physical asymmetry.

Selected by Giuliana Clemente

Categories: cell biology

Context and Background:

Cells of a developing organism can undergo either symmetric or asymmetric cell division. Upon symmetric cell division, the dividing cell generates two daughters of identical fate and size. Asymmetric cell division is a peculiar trait of stem cells and it serves both, self-renewal as well as lineage commitment and differentiation. In the context of cell division, asymmetry is generally meant as asymmetric inheritance of cell fate determinants or as a difference in the type and strength of signal(s) received from the niche. Furthermore, this form of division is often accompanied by asymmetry in cell size.

Drosophila Neuroblasts (NBs) represent a well-established system to study asymmetric stem cell division. These are large cells that repetitively divide to generate another self-renewing neuroblast and a smaller progenitor known as Ganglion Mother Cell (GMC). Neuroblasts generate cell-fate asymmetry by the establishment of a robust polarity axis. The generation of the polarity cues allows the cells to segregate fate determinants to the basal side, ensuring their subsequent inheritance by the future GMC. How cell size asymmetry is generated in the system is still somewhat elusive. Some evidence suggests that an apical-to-basal flow of Myosin-II provides a mean to generate unequally sized daughter cells (Cabernard et al, 2010; Connel et al. 2011; Ou et al. 2010). However it is still unclear by which mechanism Myosin-II promotes physical asymmetry and whether other forces acting on the system contribute to the outcome.

Key findings:

Pham et al. combine atomic force microscopy with the amenability and genetic power of Drosophila and suggest a multi-step model in which coordinated and dynamic changes in cortical tension and hydrostatic pressure direct apical membrane expansion and basal constriction, resulting in sibling size asymmetry (Figure 1). Specifically, they propose that an increase in internal pressure accompanied by a reduction in apical cortical tension drives apical expansion. At the onset of anaphase, once the internal pressure levels drastically reduce to basal level, a contractile ring forms shifted toward the basal side. This basal constriction starts basal membrane expansion and supports apical expansion as well.

 

Figure1: Proposed working model adopted from Figure 4 of the preprint.

 

Why I chose this paper:

Are cells smart entities able to receive, interpret and integrate multiple signals and tune their response accordingly? The question of cell intelligence is the big mystery that has been fascinating scientists for decades. How do cells know their relationship with the external environment? How are they able to travel long distances and get to the right place at the right time? Similarly, how do cells know what their right size should be in relation with the outer space and how do they tune their size during growth and division?

I chose the work from Pham and colleagues as they aim to address this latter question by trying to set a molecular base to the establishment of sibling cell asymmetry. This is physiologically relevant especially in the stem cell field, where keeping the right size ratio between the two daughter cells is crucial for cell specification and determination (Ou et al., 2010).

Questions for the Authors:

As the authors mention in the discussion, there is still space for a better characterisation of the process. The model indeed does not explain how internal pressure increases and whether this is under cell-cycle control. Another question would be: what is the membrane reservoir? Is new membrane delivered asymmetrically or asymmetric lipid distribution is achieved lately through the activity of the acto-myosin ring?

This area of research is undoubtedly expanding. In fact, on a smaller scale, one could ask how do cells know the size of their organelles? And by what molecular mechanisms do they control it? In this regard a good example has been recently offered by the Raff lab that published about regulation of centriole size and identified in Plk-4 the “homeostatic clock” which sets the time and rate of centriole growth (Aydogan M. G. et al., 2018).

References:

1. Cabernard, C., Prehoda, K.E., Doe, C.Q., 2010. A spindle-independent cleavage furrow positioning

pathway. Nature 467, 91–94. doi:10.1038/nature09334

2. Connell, M., Cabernard, C., Ricketson, D., Doe, C.Q., Prehoda, K.E., 2011. Asymmetric cortical

extension shifts cleavage furrow position in Drosophila neuroblasts. Mol. Biol. Cell 22, 4220–4226

doi:10.1091/mbc.E11-02-0173

3. Ou, G., Stuurman, N., D’Ambrosio, M., Vale, R.D., 2010. Polarized myosin produces unequal-size

daughters during asymmetric cell division. Science 330, 677–680. doi:10.1126/science.1196112

4. Mustafa G. Aydogan, ProAlan WainmanSaroj Saurya, Thomas L. Steinacker, Anna Caballe, Zsofia A. Novak, Janina Baumbach, Nadine Muschalik, Jordan W. Raff. A homeostatic clock sets daughter centriole size in flies. Journal of Cell Biology 217 (4), 1233-1248. doi: 10.1083/jcb.201801014

 

 

 

Posted on: 24th June 2018 , updated on: 25th June 2018

Read preprint (No Ratings Yet)




  • Have your say

    Your email address will not be published. Required fields are marked *

    Sign up to customise the site to your preferences and to receive alerts

    Register here

    Also in the cell biology category:

    SABER enables highly multiplexed and amplified detection of DNA and RNA in cells and tissues

    Jocelyn Y. Kishi, Brian J. Beliveau, Sylvain W. Lapan, et al.



    Selected by Yen-Chung Chen

    PIKfyve/Fab1 is required for efficient V-ATPase and hydrolase delivery to phagosomes, phagosomal killing, and restriction of Legionella infection

    Catherine M Buckley, Victoria L Heath, Aurelie Gueho, et al.



    Selected by Giuliana Clemente

    1

    Memory sequencing reveals heritable single cell gene expression programs associated with distinct cellular behaviors

    Sydney M Shaffer, Benjamin L Emert, Ann E. Sizemore, et al.



    Selected by Leighton Daigh

    1

    Aurora A depletion reveals centrosome-independent polarization mechanism in C. elegans

    Kerstin Klinkert, Nicolas Levernier, Peter Gross, et al.

    AND

    Centrosome Aurora A gradient ensures a single PAR-2 polarity axis by regulating RhoGEF ECT-2 localization in C. elegans embryos

    Sachin Kotak, Sukriti Kapoor



    Selected by Giuliana Clemente

    Anti-angiogenic effects of VEGF stimulation on endothelium deficient in phosphoinositide recycling

    Amber N Stratman, Olivia M Farrelly, Constantinos M Mikelis, et al.



    Selected by Coert Margadant

    Neural crest cells regulate optic cup morphogenesis by promoting extracellular matrix assembly

    Chase Dallas Bryan, Rebecca Lynne Pfeiffer, Bryan William Jones, et al.



    Selected by Ashrifia Adomako-Ankomah

    1

    mRNA localisation in endothelial cells regulates blood vessel sprouting

    Guilherme Costa, Nawseen Tarannum, Shane Herbert



    Selected by Andreas van Impel

    Local protein synthesis in axon terminals and dendritic spines differentiates plasticity contexts

    Anne-Sophie Hafner, Paul Donlin-Asp, Beulah Leitch, et al.



    Selected by Dipen Rajgor

    The cytoskeleton as a smart composite material: A unified pathway linking microtubules, myosin-II filaments and integrin adhesions

    Nisha Mohd Rafiq, Yukako Nishimura, Sergey V. Plotnikov, et al.



    Selected by Coert Margadant

    Quantitative, real-time, single cell analysis in tissue reveals expression dynamics of neurogenesis

    Cerys S Manning, Veronica Biga, James Boyd, et al.



    Selected by Teresa Rayon

    Profiling the surface proteome identifies actionable biology for TSC1 mutant cells beyond mTORC1 signaling

    Junnian Wei, Kevin K. Leung, Charles Truillet, et al.



    Selected by Rob Hynds

    1

    Optogenetic dissection of mitotic spindle positioning in vivo

    Lars-Eric Fielmich, Ruben Schmidt, Daniel J Dickinson, et al.



    Selected by Angika Basant

    1

    Excitable RhoA dynamics drive pulsed contractions in the early C. elegans embryo.

    Jonathan B Michaux, Francois B Robin, William M McFadden, et al.



    Selected by Sundar Naganathan

    Moving beyond P values: Everyday data analysis with estimation plots

    Joses Ho, Tayfun Tumkaya, Sameer Aryal, et al.



    Selected by Gautam Dey

    1

    A limited number of double-strand DNA breaks are sufficient to delay cell cycle progression.

    Jeroen van den Berg, Anna G. Manjon, Karoline Kielbassa, et al.



    Selected by Leighton Daigh

    Optogenetic manipulation of medullary neurons in the locust optic lobe

    Hongxia Wang, Richard B. Dewell, Markus U. Ehrengruber, et al.



    Selected by Ana Patricia Ramos
    Close