scholarly journals Switching between blebbing and lamellipodia depends on the degree of Nonmuscle Myosin II activity

2020 ◽  
pp. jcs.248732
Author(s):  
Indranil Ghosh ◽  
Raman K. Singh ◽  
Manjari Mishra ◽  
Shobhna Kapoor ◽  
Siddhartha S. Jana
Keyword(s):  
Atpase Activity ◽  
Myosin Ii ◽  
Relative Activity ◽  
Membrane Protrusion ◽  
Nonmuscle Myosin ◽  
Rock Inhibitor ◽  
Nonmuscle Myosin Ii ◽  
A Cell ◽  
Determining Factor

Cells can adopt both mesenchymal and amoeboid mode of migration through membrane protrusive activities, namely lamellipodia and blebbing. How the molecular players control the transition between lamellipodia and blebbing is yet to be explored. Here, we show that addition of ROCK inhibitor, Y27632 or lower doses of (-) blebbistatin, an inhibitor of NMII ATPase activity and filament partitioning, induces blebbing to lamellipodia conversion (BLC), whereas addition of lower doses of ML7, an inhibitor of MLCK, induces lamellipodia to blebbing conversion (LBC) in human MDA-MB-231 cells. Similarly, siRNA mediated knockdown of ROCK and MLCK induces BLC and LBC, respectively. Interestingly, both blebbing and lamellipodia membrane protrusion are able to maintain pRLC/RLC ratio at cortices when MLCK and ROCK are inhibited, respectively, either pharmacologically or genetically, suggesting that they are interlinked in BLC and LBC. Such BLC and LBC are also inducible in other cells like MCF7 and MCF10A. These studies reveal that relative activity of ROCK and MLCK, which controls both NMII's ATPase activity and filamentous property is a determining factor for a cell to exhibit blebbing or lamellipodia.

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.

scholarly journals 220- and 130-kDa MLCKs have distinct tissue distributions and intracellular localization patterns

2002 ◽  
Vol 282 (3) ◽  
pp. C451-C460 ◽  
Author(s):  
Emily K. Blue ◽  
Zoe M. Goeckeler ◽  
Yijun Jin ◽  
Ling Hou ◽  
Shelley A. Dixon ◽  
...  
Keyword(s):  
Intracellular Trafficking ◽  
Myosin Light Chain ◽  
Adult Mouse ◽  
Intracellular Localization ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Functional Roles ◽  
Nonmuscle Myosin Ii ◽  
Mouse Tissues

To better understand the distinct functional roles of the 220- and 130-kDa forms of myosin light chain kinase (MLCK), expression and intracellular localization were determined during development and in adult mouse tissues. Northern blot, Western blot, and histochemical studies show that the 220-kDa MLCK is widely expressed during development as well as in several adult smooth muscle and nonmuscle tissues. The 130-kDa MLCK is highly expressed in all adult tissues examined and is also detectable during embryonic development. Colocalization studies examining the distribution of 130- and 220-kDa mouse MLCKs revealed that the 130-kDa MLCK colocalizes with nonmuscle myosin IIA but not with myosin IIB or F-actin. In contrast, the 220-kDa MLCK did not colocalize with either nonmuscle myosin II isoform but instead colocalizes with thick interconnected bundles of F-actin. These results suggest that in vivo, the physiological functions of the 220- and 130-kDa MLCKs are likely to be regulated by their intracellular trafficking and distribution.

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