The Role of Actomyosin Contractility During Early Avian Gastrulation

2010 ◽  
Author(s):  
Drew Owen ◽  
Evan Zamir
Keyword(s):  
Cell Movement ◽  
Primitive Streak ◽  
Higher Order ◽  
Specific Role ◽  
Germ Layers ◽  
Morphogenetic Movements ◽  
Actomyosin Contractility ◽  
Organizing Center ◽  
Cell Intercalation

Actin-myosin contraction has been shown to play a major role in early morphogenetic movements in Drosophila (fly) and Xenopus (frog) [1,2]. However, the specific role of actomyosin contractility in amniote embryos (reptiles, birds, and mammals) during primitive streak (PS) formation, the “organizing center” for gastrulation (formation of three primary germ layers), is not known. Current theories regarding primitive streak formation in higher order amniotes center around cell-cell intercalation or chemotactic cell movement [3,4]. We hypothesize that contraction via actin-myosin (AM) filaments is conserved from anamniotes and drives formation of the PS and the associated morphogenetic cell movements.

Interpassivity and Misdemeanours: The Art of Thinking in Examples and the Žižekian Toolbox

2018 ◽  
Author(s):  
Robert Pfaller
Keyword(s):  
Specific Role ◽  
Slavoj Zizek ◽  
Slavoj Žižek ◽  
The Sublime

Starting from a passage from Slavoj Žižek`s brilliant book The Sublime Object of Ideology, the very passage on canned laughter that gave such precious support for the development of the theory of interpassivity, this chapter examines a question that has proved indispensable for the study of interpassivity: namely, what does it mean for a theory to proceed by examples? What is the specific role of the example in certain example-friendly theories, for example in Žižek’s philosophy?

Current Study of RhoA and Associated Signaling Pathways in Gastric Cancer

2020 ◽  
Vol 15 (7) ◽  
pp. 607-613 ◽  
Author(s):  
Haiping Liu ◽  
Yiqian Liu ◽  
Xiaochuan Zhang ◽  
Xiaodong Wang
Keyword(s):  
Gastric Cancer ◽  
Survival Rate ◽  
Signaling Pathways ◽  
Tumor Cells ◽  
Actin Polymerization ◽  
Cell Transformation ◽  
Cell Movement ◽  
Invasion And Metastasis ◽  
Common Cancer

Gastric cancer (GC) is the fourth-most common cancer in the world, with an estimated 1.034 million new cases in 2015, and the third-highest cause of cancer deaths, estimated at 785,558, in 2014. Early diagnosis and treatment greatly affect the survival rate in patients with GC: the 5‐year survival rate of early GC reaches 90%‐95%, while the mortality rate significantly increases if GC develops to the late stage. Recently, studies for the role of RhoA in the diseases have become a hot topic, especially in the development of tumors. A study found that RhoA can regulate actin polymerization, cell adhesion, motor-myosin, cell transformation, and the ability to participate in the activities of cell movement, proliferation, migration, which are closely related to the invasion and metastasis of tumor cells. However, the specific role of RhoA in tumor cells remains to be studied. Therefore, our current study aimed to briefly review the role of RhoA in GC, especially for its associated signaling pathways involved in the GC progression.

scholarly journals A Sex-Specific Role of Endothelial Sirtuin 3 on Blood Pressure and Diastolic Dysfunction in Female Mice

2020 ◽  
Vol 21 (24) ◽  
pp. 9744
Author(s):  
Heng Zeng ◽  
Xiaochen He ◽  
Jian-Xiong Chen
Keyword(s):  
Blood Pressure ◽  
Diastolic Dysfunction ◽  
Diastolic Function ◽  
Normal Diet ◽  
Specific Role ◽  
Sirtuin 3 ◽  
Control Female ◽  
Female Mice ◽  
Flow Reserve

Background: Heart failure with preserved ejection fraction (HFpEF) is characterized by a diastolic dysfunction and is highly prevalent in aged women. Our study showed that ablation of endothelial Sirtuin 3 (SIRT3) led to diastolic dysfunction in male mice. However, the sex-specific role of endothelial SIRT3 deficiency on blood pressure and diastolic function in female mice remains to be investigated. Methods and Results: In this study, we demonstrate that the ablation of endothelial SIRT3 in females elevated blood pressure as compared with control female mice. Diastolic function measurement also showed that the isovolumic relaxation time (IVRT) and myocardial performance index (MPI) were significantly increased, whereas the E’ velocity/A’ velocity (E’/A’) ratio was reduced in the endothelial-specific SIRT3 knockout (SIRT3 ECKO) female mice. To further investigate the regulatory role of endothelial SIRT3 on blood pressure and diastolic dysfunction in metabolic stress, SIRT3 ECKO female mice were fed a normal diet and high-fat diet (HFD) for 20 weeks. The knockout of endothelial SIRT3 resulted in an increased blood pressure in female mice fed with an HFD. Intriguingly, SIRT3 ECKO female mice + HFD exhibited impaired coronary flow reserve (CFR) and more severe diastolic dysfunction as evidenced by an elevated IVRT as compared with control female mice + HFD. In addition, female SIRT3 ECKO mice had higher blood pressure and diastolic dysfunction as compared to male SIRT3 ECKO mice. Moreover, female SIRT3 ECKO mice + HFD had an impaired CFR and diastolic dysfunction as compared to male SIRT3 ECKO mice + HFD. Conclusions: These results implicate a sex-specific role of endothelial SIRT3 in regulating blood pressure and diastolic function in mice. Deficiency of endothelial SIRT3 may be responsible for a diastolic dysfunction in aged female.

scholarly journals Protein farnesylation is upregulated in Alzheimer’s human brains and neuron-specific suppression of farnesyltransferase mitigates pathogenic processes in Alzheimer’s model mice

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Angela Jeong ◽  
Shaowu Cheng ◽  
Rui Zhong ◽  
David A. Bennett ◽  
Martin O. Bergö ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Small Gtpases ◽  
Specific Role ◽  
Postmortem Brain ◽  
Effective Prevention ◽  
Postmortem Brain Tissue ◽  
Mtorc1 Signaling ◽  
Behavioral Assessments ◽  
Human Brains

AbstractThe pathogenic mechanisms underlying the development of Alzheimer’s disease (AD) remain elusive and to date there are no effective prevention or treatment for AD. Farnesyltransferase (FT) catalyzes a key posttranslational modification process called farnesylation, in which the isoprenoid farnesyl pyrophosphate is attached to target proteins, facilitating their membrane localization and their interactions with downstream effectors. Farnesylated proteins, including the Ras superfamily of small GTPases, are involved in regulating diverse physiological and pathological processes. Emerging evidence suggests that isoprenoids and farnesylated proteins may play an important role in the pathogenesis of AD. However, the dynamics of FT and protein farnesylation in human brains and the specific role of neuronal FT in the pathogenic progression of AD are not known. Here, using postmortem brain tissue from individuals with no cognitive impairment (NCI), mild cognitive impairment (MCI), or Alzheimer’s dementia, we found that the levels of FT and membrane-associated H-Ras, an exclusively farnesylated protein, and its downstream effector ERK were markedly increased in AD and MCI compared with NCI. To elucidate the specific role of neuronal FT in AD pathogenesis, we generated the transgenic AD model APP/PS1 mice with forebrain neuron-specific FT knockout, followed by a battery of behavioral assessments, biochemical assays, and unbiased transcriptomic analysis. Our results showed that the neuronal FT deletion mitigates memory impairment and amyloid neuropathology in APP/PS1 mice through suppressing amyloid generation and reversing the pathogenic hyperactivation of mTORC1 signaling. These findings suggest that aberrant upregulation of protein farnesylation is an early driving force in the pathogenic cascade of AD and that targeting FT or its downstream signaling pathways presents a viable therapeutic strategy against AD.

scholarly journals Stage-Dependent and Locus-Specific Role of Histone Demethylase Jumonji D3 (JMJD3) in the Embryonic Stages of Lung Development

PLoS Genetics ◽  
2014 ◽  
Vol 10 (7) ◽  
pp. e1004524 ◽  
Author(s):  
Qingtian Li ◽  
Helen Y. Wang ◽  
Iouri Chepelev ◽  
Qingyuan Zhu ◽  
Gang Wei ◽  
...  
Keyword(s):  
Lung Development ◽  
Histone Demethylase ◽  
Specific Role
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