Faculty Opinions recommendation of Force-dependent activation of actin elongation factor mDia1 protects the cytoskeleton from mechanical damage and facilitates stress fiber repair.

2021 ◽  
Author(s):  
Guillaume Romet-Lemonne
Keyword(s):  
Mechanical Damage ◽  
Elongation Factor ◽  
Stress Fiber

scholarly journals Force-dependent activation of actin elongation factor mDia1 protects the cytoskeleton from mechanical damage and facilitates stress fiber repair

2021 ◽  
Author(s):  
Fernando R. Valencia ◽  
Eduardo Sandoval ◽  
Jian Liu ◽  
Sergey V. Plotnikov
Keyword(s):  
Cell Mechanics ◽  
Actin Polymerization ◽  
Safety Valve ◽  
Mechanical Damage ◽  
Elongation Factor ◽  
Focal Adhesions ◽  
Stress Fiber ◽  
Stress Fibers ◽  
Mechanical Tension ◽  
Contractile Forces

ABSTRACTPlasticity of cell mechanics, which relies heavily on the spatiotemporal regulation of the actomyosin cytoskeleton, safeguards cells against mechanical damage. Yet, mechanisms of adaptive change in cell mechanics remain elusive. Here, we report a new mechanism whereby mechanically activated actin elongation factor mDia1 controls the dynamics of actin polymerization at focal adhesions, force bearing linkages between the actin cytoskeleton and extracellular matrix. By combining live-cell imaging with mathematical modelling, we show that actin polymerization at focal adhesions exhibits pulsatile dynamics where the spikes of mDia1 activity are triggered by cell-generated contractile forces. We show that suppression of mDia1-mediated actin polymerization at focal adhesions results in two-fold increase in mechanical tension on the stress fibers. This elevated tension leads to an increased frequency of spontaneous stress fiber damage and decreased efficiency of zyxin-mediated stress fiber repair. We conclude that tension-controlled actin polymerization at focal adhesions acts as a safety valve dampening excessive mechanical tension on the actin cytoskeleton and safeguarding stress fibers against mechanical damage.SUMMARYValencia et al. reports that stress fiber elongation at focal adhesion requires mDia1 activity, furthermore contractile forces trigger mDia1-dependent actin polymerization. mDia1-mediated actin polymerization acts as a safety valve to dampen mechanical stress and protect the cell from damage.

Analysis of senescence-responsive stress fiber proteome reveals reorganization of stress fibers mediated by elongation factor eEF2 in HFF-1 cells

2021 ◽  
Author(s):  
Shiyou Liu ◽  
Tsubasa S. Matsui ◽  
Na Kang ◽  
Shinji Deguchi
Keyword(s):  
Replicative Senescence ◽  
Human Fibroblasts ◽  
Elongation Factor ◽  
Stress Fiber ◽  
Stress Fibers ◽  
Translation Elongation Factor ◽  
Translation Elongation ◽  
Eukaryotic Translation ◽  
Elongation Factor 2 ◽  
Protein Components

Stress fibers (SFs), which are actomyosin structures, reorganize in response to various cues to maintain cellular homeostasis. Currently, the protein components of SFs are only partially identified, limiting our understanding of their responses. Here we isolate SFs from human fibroblasts HFF-1 to determine with proteomic analysis the whole protein components and how they change with replicative senescence (RS), a state where cells decline in ability to replicate after repeated divisions. We found that at least 135 proteins are associated with SFs, and 63 of them are upregulated with RS, by which SFs become larger in size. Among them, we focused on eEF2 (eukaryotic translation elongation factor 2) as it exhibited upon RS the most significant increase in abundance. We show that eEF2 is critical to the reorganization and stabilization of SFs in senescent fibroblasts. Our findings provide a novel molecular basis for SFs to be reinforced to resist cellular senescence.

Use of the electro-separation method for improvement of the utility value of winter rapeseeds

2013 ◽  
Vol 27 (4) ◽  
pp. 419-424 ◽  
Author(s):  
S.J. Kovalyshyn ◽  
O.P. Shvets ◽  
S. Grundas ◽  
J. Tys
Keyword(s):  
Corona Discharge ◽  
Mechanical Damage ◽  
Edible Oil ◽  
Separation Method ◽  
Utility Value ◽  
X Ray ◽  
Winter Rapeseed ◽  
The Mean ◽  
Discharge Field ◽  
Prototype Apparatus

Abstract The paper presents the results of a study of the use of electro-separation methods for improvement of the utility value of 5 winter rapeseed cultivars. The process of electro-separation of rapeseed was conducted on a prototype apparatus built at the Laboratory of Application of Electro-technologies in Agriculture, Lviv National Agriculture University. The process facilitated separation of damaged, low quality seeds from the sowing material. The initial mean level of mechanically damaged seeds in the winter rapeseed cultivars studied varied within the range of 15.8-20.1%. Verification of the amount of seeds with mechanical damage was performed on X-ray images of seeds acquired by means of a digital X-ray apparatus. In the course of analysis of the X-ray images, it was noted that the mean level of mechanical damage to the seeds after the electro-separation was in the range of 2.1-3.8%. The application of the method of separation of rapeseeds in the corona discharge field yielded a significant reduction of the level of seeds with mechanical damage. The application of the method in practice may effectively contribute to improvement of the utility value of sowing material or seed material for production of edible oil.

Diseases of the kumara crop

2009 ◽  
Vol 62 ◽  
pp. 402-402
Author(s):  
S.L. Lewthwaite ◽  
P.J. Wright
Keyword(s):  
Fungal Pathogens ◽  
Ipomoea Batatas ◽  
Mechanical Damage ◽  
Soft Rot ◽  
Economic Loss ◽  
Root Surface ◽  
Black Rot ◽  
Rhizopus Stolonifer ◽  
Ceratocystis Fimbriata ◽  
Pink Rot

The predominant diseases of the commercial kumara (Ipomoea batatas) or sweetpotato crop are caused by fungal pathogens The field disease pink rot results from infection by the fungus Sclerotinia sclerotiorum Lesions form on vines but may spread down stems to the roots The widespread nature of this disease in sweetpotato appears peculiar to New Zealand Scurf is a disease caused by Monilochaetes infuscans which occurs in the field but may proliferate amongst stored roots The disease causes a superficial discolouration of the root surface which is mainly cosmetic but can also increase root water loss in storage Infection by Ceratocystis fimbriata produces a disease known as black rot The disease can be transmitted amongst plants at propagation but is particularly rampant amongst roots in storage This disease is readily transmitted and can cause severe economic loss Fusarium oxysporum causes surface rots in stored roots characterised by light to dark brown lesions that tend to be firm dry and superficial The lesions may be circular and centred on wounds caused by insects or mechanical damage at harvest Soft rot caused by Rhizopus stolonifer generally occurs in roots after they are washed and prepared for the market Fungal infection occurs through wounds or bruised tissue producing distinctive tufts of white fungal strands and black spores

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