scholarly journals Cytoskeleton actin-binding proteins in clinical behavior of pituitary tumors

2019 ◽  
Vol 26 (2) ◽  
pp. R95-R108 ◽  
Author(s):  
G Mantovani ◽  
D Treppiedi ◽  
E Giardino ◽  
R Catalano ◽  
F Mangili ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Pituitary Tumors ◽  
Somatostatin Analogues ◽  
Biological Behavior ◽  
Actin Binding ◽  
Filamin A ◽  
Key Factor ◽  
Dopamine Analogues ◽  
And Function

Although generally benign, pituitary tumors are frequently locally invasive, with reduced success of neurosurgery and unresponsive to pharmacological treatment with somatostatin or dopamine analogues. The molecular basis of the different biological behavior of pituitary tumors are still poorly identified, but a body of work now suggests that the activity of specific cytoskeleton proteins is a key factor regulating both the invasiveness and drug resistance of these tumors. This review recapitulates the experimental evidence supporting a role for the actin-binding protein filamin A (FLNA) in the regulation of somatostatin and dopamine receptors expression and signaling in pituitary tumors, thus in determining the responsiveness to currently used drugs, somatostatin analogues and dopamine receptor type 2 agonists. Regarding the regulation of invasive behavior of pituitary tumoral cells, we bring evidence to the role of the actin-severing protein cofilin, whose activation status may be modulated by dopaminergic and somatostatinergic drugs, through FLNA involvement. Molecular mechanisms involved in the regulation of FLNA expression and function in pituitary tumors will also be discussed.

scholarly journals Structure and Function of Filamin C in the Muscle Z-Disc

2020 ◽  
Vol 21 (8) ◽  
pp. 2696 ◽  
Author(s):  
Zhenfeng Mao ◽  
Fumihiko Nakamura
Keyword(s):  
Sequence Similarity ◽  
Actin Binding ◽  
Amino Acid Residues ◽  
Filamin A ◽  
Dimerization Domain ◽  
High Sequence Similarity ◽  
Actin Binding Domain ◽  
And Function ◽  
Filamin C

Filamin C (FLNC) is one of three filamin proteins (Filamin A (FLNA), Filamin B (FLNB), and FLNC) that cross-link actin filaments and interact with numerous binding partners. FLNC consists of a N-terminal actin-binding domain followed by 24 immunoglobulin-like repeats with two intervening calpain-sensitive hinges separating R15 and R16 (hinge 1) and R23 and R24 (hinge-2). The FLNC subunit is dimerized through R24 and calpain cleaves off the dimerization domain to regulate mobility of the FLNC subunit. FLNC is localized in the Z-disc due to the unique insertion of 82 amino acid residues in repeat 20 and necessary for normal Z-disc formation that connect sarcomeres. Since phosphorylation of FLNC by PKC diminishes the calpain sensitivity, assembly, and disassembly of the Z-disc may be regulated by phosphorylation of FLNC. Mutations of FLNC result in cardiomyopathy and muscle weakness. Although this review will focus on the current understanding of FLNC structure and functions in muscle, we will also discuss other filamins because they share high sequence similarity and are better characterized. We will also discuss a possible role of FLNC as a mechanosensor during muscle contraction.

scholarly journals The roles and mechanisms of hypoxia in liver fibrosis

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jingyao Cai ◽  
Min Hu ◽  
Zhiyang Chen ◽  
Zeng Ling
Keyword(s):  
Quality Of Life ◽  
Liver Fibrosis ◽  
Theoretical Basis ◽  
Liver Diseases ◽  
Molecular Mechanisms ◽  
Clinical Intervention ◽  
Chronic Liver Injury ◽  
Key Factor

AbstractLiver fibrosis occurs in response to any etiology of chronic liver injury. Lack of appropriate clinical intervention will lead to liver cirrhosis or hepatocellular carcinoma (HCC), seriously affecting the quality of life of patients, but the current clinical treatments of liver fibrosis have not been developed yet. Recent studies have shown that hypoxia is a key factor promoting the progression of liver fibrosis. Hypoxia can cause liver fibrosis. Liver fibrosis can, in turn, profoundly further deepen the degree of hypoxia. Therefore, exploring the role of hypoxia in liver fibrosis will help to further understand the process of liver fibrosis, and provide the theoretical basis for its diagnosis and treatment, which is of great significance to avoid further deterioration of liver diseases and protect the life and health of patients. This review highlights the recent advances in cellular and molecular mechanisms of hypoxia in developments of liver fibrosis.

scholarly journals Mechanosensitive Ion Channel Piezo1 Regulates Myocyte Fusion during Skeletal Myogenesis

2020 ◽  
Author(s):  
Huascar Pedro Ortuste Quiroga ◽  
Shingo Yokoyama ◽  
Massimo Ganassi ◽  
Kodai Nakamura ◽  
Tomohiro Yamashita ◽  
...  
Keyword(s):  
Ion Channel ◽  
Molecular Mechanisms ◽  
Myoblast Fusion ◽  
Mechanical Stimuli ◽  
Muscle Satellite Cell ◽  
Myotube Formation ◽  
Mechanosensitive Ion Channel ◽  
And Function ◽  
Sirna Knockdown

AbstractMechanical stimuli such as stretch and resistance training are essential to regulate growth and function of skeletal muscle. However, the molecular mechanisms involved in sensing mechanical stress remain unclear. Here, the purpose of this study was to investigate the role of the mechanosensitive ion channel Piezo1 during myogenic progression. Muscle satellite cell-derived myoblasts and myotubes were modified with stretch, siRNA knockdown and agonist-induced activation of Piezo1. Direct manipulation of Piezo1 modulates terminal myogenic progression. Piezo1 knockdown suppressed myoblast fusion during myotube formation and maturation. This was accompanied by downregulation of the fusogenic protein Myomaker. Piezo1 knockdown also lowered Ca2+ influx in response to stretch. Conversely Piezo1 activation stimulated fusion and increased Ca2+ influx in response to stretch. These evidences indicate that Piezo1 is essential for myotube formation and maturation, which may have implications for msucular dystrophy prevention through its role as a mechanosensitive Ca2+ channel.

scholarly journals The role of Asprosin in patients with dilated cardiomyopathy

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ming-Shien Wen ◽  
Chao-Yung Wang ◽  
Jih-Kai Yeh ◽  
Chun-Chi Chen ◽  
Ming-Lung Tsai ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Mitochondrial Respiration ◽  
Cardiovascular Events ◽  
Molecular Mechanisms ◽  
Major Adverse Cardiovascular Events ◽  
Study Cohort ◽  
Protective Mechanisms ◽  
Mitochondrial Functions ◽  
And Function

Abstract Background Asprosin is a novel fasting glucogenic adipokine discovered in 2016. Asprosin induces rapid glucose releases from the liver. However, its molecular mechanisms and function are still unclear. Adaptation of energy substrates from fatty acid to glucose is recently considered a novel therapeutic target in heart failure treatment. We hypothesized that the asprosin is able to modulate cardiac mitochondrial functions and has important prognostic implications in dilated cardiomyopathy (DCM) patients. Methods We prospectively enrolled 50 patients (86% male, mean age 55 ± 13 years) with DCM and followed their 5-year major adverse cardiovascular events from 2012 to 2017. Comparing with healthy individuals, DCM patients had higher asprosin levels (191.2 versus 79.7 ng/mL, P < 0.01). Results During the 5-year follow-up in the study cohort, 16 (32.0%) patients experienced adverse cardiovascular events. Patients with lower asprosin levels (< 210 ng/mL) were associated with increased risks of adverse clinical outcomes with a hazard ratio of 7.94 (95% CI 1.88–33.50, P = 0.005) when compared patients with higher asprosin levels (≥ 210 ng/mL). Using cardiomyoblasts as a cellular model, we showed that asprosin prevented hypoxia-induced cell death and enhanced mitochondrial respiration and proton leak under hypoxia. Conclusions In patients with DCM, elevated plasma asprosin levels are associated with less adverse cardiovascular events in five years. The underlying protective mechanisms of asprosin may be linked to its functions relating to enhanced mitochondrial respiration under hypoxia.

New functions for old factors: the role of polyamines during the establishment of pregnancy

2019 ◽  
Vol 31 (7) ◽  
pp. 1228
Author(s):  
Jane C. Fenelon ◽  
Bruce D. Murphy
Keyword(s):  
Molecular Mechanisms ◽  
New Technologies ◽  
Alternative Pathway ◽  
Rapid Expansion ◽  
Polyamine Synthesis ◽  
Recent Developments ◽  
And Function ◽  
Implantation Period ◽  
Synthesis Regulation

Implantation is essential for the establishment of a successful pregnancy, and the preimplantation period plays a significant role in ensuring implantation occurs in a timely and coordinated manner. This requires effective maternal–embryonic signalling, established during the preimplantation period, to synchronise development. Although multiple factors have been identified as present during this time, the exact molecular mechanisms involved are unknown. Polyamines are small cationic molecules that are ubiquitously expressed from prokaryotes to eukaryotes. Despite being first identified over 300 years ago, their essential roles in cell proliferation and growth, including cancer, have only been recently recognised, with new technologies and interest resulting in rapid expansion of the polyamine field. This review provides a summary of our current understanding of polyamine synthesis, regulation and function with a focus on recent developments demonstrating the requirements for polyamines during the establishment of pregnancy up to the implantation stage, in particular the role of polyamines in the control of embryonic diapause and the identification of an alternative pathway for their synthesis in sheep pregnancy. This, along with other novel discoveries, provides new insights into the control of the peri-implantation period in mammals and highlights the complexities that exist in regulating this critical period of pregnancy.

The role of mitochondria in axonal degeneration and tissue repair in MS

2012 ◽  
Vol 18 (8) ◽  
pp. 1058-1067 ◽  
Author(s):  
J van Horssen ◽  
ME Witte ◽  
O Ciccarelli
Keyword(s):  
Mitochondrial Dysfunction ◽  
Tissue Repair ◽  
Molecular Mechanisms ◽  
Axonal Degeneration ◽  
Axonal Damage ◽  
Mitochondrial Metabolism ◽  
Imaging Studies ◽  
And Function

Axonal injury is a key feature of multiple sclerosis (MS) pathology and is currently seen as the main correlate for permanent clinical disability. Although little is known about the pathogenetic mechanisms that drive axonal damage and loss, there is accumulating evidence highlighting the central role of mitochondrial dysfunction in axonal degeneration and associated neurodegeneration. The aim of this topical review is to provide a concise overview on the involvement of mitochondrial dysfunction in axonal damage and destruction in MS. Hereto, we will discuss putative pathological mechanisms leading to mitochondrial dysfunction and recent imaging studies performed in vivo in patients with MS. Moreover, we will focus on molecular mechanisms and novel imaging studies that address the role of mitochondrial metabolism in tissue repair. Finally, we will briefly review therapeutic strategies aimed at improving mitochondrial metabolism and function under neuroinflammatory conditions.

The Role of Actin-Binding Protein Filamin A in Cellular Stiffness and Morphology Studied by Wide-Range Scanning Probe Microscopy

2006 ◽  
Vol 45 (3B) ◽  
pp. 2328-2332 ◽  
Author(s):  
Kosaku Kato ◽  
Yukiko Ohmori ◽  
Takeomi Mizutani ◽  
Hisashi Haga ◽  
Kazuyo Ohashi ◽  
...  
Keyword(s):  
Scanning Probe Microscopy ◽  
Binding Protein ◽  
Scanning Probe ◽  
Actin Binding ◽  
Filamin A ◽  
Probe Microscopy ◽  
Actin Binding Protein ◽  
Wide Range ◽  
Range Scanning

scholarly journals Recent progress in research on molecular mechanisms of autophagy in the heart

2015 ◽  
Vol 308 (4) ◽  
pp. H259-H268 ◽  
Author(s):  
Yasuhiro Maejima ◽  
Yun Chen ◽  
Mitsuaki Isobe ◽  
Åsa B. Gustafsson ◽  
Richard N. Kitsis ◽  
...  
Keyword(s):  
Heart Disease ◽  
Molecular Mechanisms ◽  
Therapeutic Potential ◽  
Degradation Process ◽  
Structure And Function ◽  
Cellular Functions ◽  
Evolutionarily Conserved ◽  
And Function ◽  
Cellular Dysfunction

Dysregulation of autophagy, an evolutionarily conserved process for degradation of long-lived proteins and organelles, has been implicated in the pathogenesis of human disease. Recent research has uncovered pathways that control autophagy in the heart and molecular mechanisms by which alterations in this process affect cardiac structure and function. Although initially thought to be a nonselective degradation process, autophagy, as it has become increasingly clear, can exhibit specificity in the degradation of molecules and organelles, such as mitochondria. Furthermore, it has been shown that autophagy is involved in a wide variety of previously unrecognized cellular functions, such as cell death and metabolism. A growing body of evidence suggests that deviation from appropriate levels of autophagy causes cellular dysfunction and death, which in turn leads to heart disease. Here, we review recent advances in understanding the role of autophagy in heart disease, highlight unsolved issues, and discuss the therapeutic potential of modulating autophagy in heart disease.

scholarly journals The Endo-Lysosomal Sorting Machinery Interacts with the Intermediate Filament Cytoskeleton

2004 ◽  
Vol 15 (12) ◽  
pp. 5369-5382 ◽  
Author(s):  
Melanie L. Styers ◽  
Gloria Salazar ◽  
Rachal Love ◽  
Andrew A. Peden ◽  
Andrew P. Kowalczyk ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Subcellular Distribution ◽  
Total Content ◽  
Actin Binding ◽  
Intermediate Filament Proteins ◽  
Lysosomal Sorting ◽  
Cytoskeletal Networks ◽  
And Function ◽  
Phenotypic Convergence

Cytoskeletal networks control organelle subcellular distribution and function. Herein, we describe a previously unsuspected association between intermediate filament proteins and the adaptor complex AP-3. AP-3 and intermediate filament proteins cosedimented and coimmunoprecipitated as a complex free of microtubule and actin binding proteins. Genetic perturbation of the intermediate filament cytoskeleton triggered changes in the subcellular distribution of the adaptor AP-3 and late endocytic/lysosome compartments. Concomitant with these architectural changes, and similarly to AP-3-null mocha cells, fibroblasts lacking vimentin were compromised in their vesicular zinc uptake, their organellar pH, and their total and surface content of AP-3 cargoes. However, the total content and surface levels, as well as the distribution of the transferrin receptor, a membrane protein whose sorting is AP-3 independent, remained unaltered in both AP-3- and vimentin-null cells. Based on the phenotypic convergence between AP-3 and vimentin deficiencies, we predicted and documented a reduced autophagosome content in mocha cells, a phenotype previously reported in cells with disrupted intermediate filament cytoskeletons. Our results reveal a novel role of the intermediate filament cytoskeleton in organelle/adaptor positioning and in regulation of the adaptor complex AP-3.

Homeostatic control of biological membranes by dedicated lipid and membrane packing sensors

2015 ◽  
Vol 396 (9-10) ◽  
pp. 1043-1058 ◽  
Author(s):  
Kristina Puth ◽  
Harald F. Hofbauer ◽  
James P. Sáenz ◽  
Robert Ernst
Keyword(s):  
Molecular Mechanisms ◽  
Biological Membranes ◽  
Homeostatic Control ◽  
Open Questions ◽  
Lipid Species ◽  
Sensor Proteins ◽  
And Function ◽  
Lipid Sensors ◽  
Role And Function

Abstract Biological membranes are dynamic and complex assemblies of lipids and proteins. Eukaryotic lipidomes encompass hundreds of distinct lipid species and we have only begun to understand their role and function. This review focuses on recent advances in the field of lipid sensors and discusses methodical approaches to identify and characterize putative sensor domains. We elaborate on the role of integral and conditionally membrane-associated sensor proteins, their molecular mechanisms, and identify open questions in the emerging field of membrane homeostasis.

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