scholarly journals Cortical contraction drives the 3D patterning of epithelial cell surfaces

2020 ◽  
Vol 219 (3) ◽  
Author(s):  
Aaron P. van Loon ◽  
Ivan S. Erofeev ◽  
Ivan V. Maryshev ◽  
Andrew B. Goryachev ◽  
Alvaro Sagasti
Keyword(s):  
Surface Tension ◽  
Myosin Ii ◽  
Biomechanical Model ◽  
Complex Cell ◽  
Nonmuscle Myosin ◽  
Cell Surfaces ◽  
Apical Constriction ◽  
Skin Cells ◽  
Nonmuscle Myosin Ii ◽  
Surface Topographies

Cellular protrusions create complex cell surface topographies, but biomechanical mechanisms regulating their formation and arrangement are largely unknown. To study how protrusions form, we focused on the morphogenesis of microridges, elongated actin-based structures that are arranged in maze-like patterns on the apical surfaces of zebrafish skin cells. Microridges form by accreting simple finger-like precursors. Live imaging demonstrated that microridge morphogenesis is linked to apical constriction. A nonmuscle myosin II (NMII) reporter revealed pulsatile contractions of the actomyosin cortex, and inhibiting NMII blocked apical constriction and microridge formation. A biomechanical model suggested that contraction reduces surface tension to permit the fusion of precursors into microridges. Indeed, reducing surface tension with hyperosmolar media promoted microridge formation. In anisotropically stretched cells, microridges formed by precursor fusion along the stretch axis, which computational modeling explained as a consequence of stretch-induced cortical flow. Collectively, our results demonstrate how contraction within the 2D plane of the cortex can pattern 3D cell surfaces.

scholarly journals Cortical contraction drives the 3D patterning of epithelial cell surfaces

2019 ◽  
Author(s):  
Aaron P. van Loon ◽  
Ivan S. Erofeev ◽  
Ivan V. Maryshev ◽  
Andrew B. Goryachev ◽  
Alvaro Sagasti
Keyword(s):  
Surface Tension ◽  
Myosin Ii ◽  
Biomechanical Model ◽  
Cell Surfaces ◽  
Apical Constriction ◽  
Skin Cells ◽  
In Vivo Experiments ◽  
Surface Topographies ◽  
Muscle Myosin

ABSTRACTCellular protrusions create complex cell surface topographies, but biomechanical mechanisms regulating their formation and arrangement are largely unknown. To study how protrusions form, we focused on the morphogenesis of microridges, elongated actin-based structures projecting from the apical surfaces of zebrafish skin cells that are arranged in labyrinthine patterns. Microridges form by accreting simple finger-like precursors. Live imaging demonstrated that microridge morphogenesis is linked to apical constriction. A non-muscle myosin II (NMII) reporter revealed pulsatile contractions of the actomyosin cortex; inhibiting NMII demonstrated that contractions are required for apical constriction and microridge formation. A biomechanical model suggested that contraction reduces surface tension to permit the fusion of precursors into microridges. Indeed, reducing surface tension with hyperosmolar media promoted microridge formation. In anisotropically stretched cells, microridges formed by precursor fusion along the stretch axis, which computational modeling explained as a consequence of stretch-induced cortical flow. Collectively, our results demonstrate how contraction within the 2D plane of the cortex patterns 3D cell surfaces.SUMMARYMicroridges, elongated 3D protrusions arranged in maze-like patterns on zebrafish skin cells, form by the accretion of simple precursor projections. Modeling and in vivo experiments showed that cortical contractions promote the coalescence of precursors into microridges by reducing membrane tension.

Nonmuscle Myosin II

2018 ◽  
pp. 3541-3553 ◽  
Author(s):  
Alba Juanes-García ◽  
Clara Llorente-González ◽  
Miguel Vicente-Manzanares
Keyword(s):  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii

scholarly journals Myosin Motors and Not Actin Comets Are Mediators of the Actin-based Golgi-to-Endoplasmic Reticulum Protein Transport

2003 ◽  
Vol 14 (2) ◽  
pp. 445-459 ◽  
Author(s):  
Juan M. Durán ◽  
Ferran Valderrama ◽  
Susana Castel ◽  
Juana Magdalena ◽  
Mónica Tomás ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Light Chain ◽  
Shiga Toxin ◽  
Actin Filaments ◽  
Protein Transport ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii ◽  
Myosin Motors

We have previously reported that actin filaments are involved in protein transport from the Golgi complex to the endoplasmic reticulum. Herein, we examined whether myosin motors or actin comets mediate this transport. To address this issue we have used, on one hand, a combination of specific inhibitors such as 2,3-butanedione monoxime (BDM) and 1-[5-isoquinoline sulfonyl]-2-methyl piperazine (ML7), which inhibit myosin and the phosphorylation of myosin II by the myosin light chain kinase, respectively; and a mutant of the nonmuscle myosin II regulatory light chain, which cannot be phosphorylated (MRLC2AA). On the other hand, actin comet tails were induced by the overexpression of phosphatidylinositol phosphate 5-kinase. Cells treated with BDM/ML7 or those that express the MRLC2AA mutant revealed a significant reduction in the brefeldin A (BFA)-induced fusion of Golgi enzymes with the endoplasmic reticulum (ER). This delay was not caused by an alteration in the formation of the BFA-induced tubules from the Golgi complex. In addition, the Shiga toxin fragment B transport from the Golgi complex to the ER was also altered. This impairment in the retrograde protein transport was not due to depletion of intracellular calcium stores or to the activation of Rho kinase. Neither the reassembly of the Golgi complex after BFA removal nor VSV-G transport from ER to the Golgi was altered in cells treated with BDM/ML7 or expressing MRLC2AA. Finally, transport carriers containing Shiga toxin did not move into the cytosol at the tips of comet tails of polymerizing actin. Collectively, the results indicate that 1) myosin motors move to transport carriers from the Golgi complex to the ER along actin filaments; 2) nonmuscle myosin II mediates in this process; and 3) actin comets are not involved in retrograde transport.

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