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Current Biology : CB May 2021Arit Ghosh and Velia Fowler introduce the structural features and functions of tropomodulins - actin-binding proteins that cap the slow-growing (pointed) ends of actin...
Arit Ghosh and Velia Fowler introduce the structural features and functions of tropomodulins - actin-binding proteins that cap the slow-growing (pointed) ends of actin filaments.
Topics: Actin Cytoskeleton; Actins; Microfilament Proteins; Tropomodulin
PubMed: 34033779
DOI: 10.1016/j.cub.2021.01.055 -
Current Biology : CB May 2021Actin is one of the most abundant proteins in eukaryotes. Discovered in muscle and described as far back as 1887, actin was first purified in 1942. It plays myriad roles...
Actin is one of the most abundant proteins in eukaryotes. Discovered in muscle and described as far back as 1887, actin was first purified in 1942. It plays myriad roles in essentially every eukaryotic cell. Actin is central to development, muscle contraction, and cell motility, and it also functions in the nucleus, to name a spectrum of examples. The flexibility of actin function stems from two factors: firstly, it is dynamic, transitioning between monomer and filament, and, secondly, there are hundreds of actin-binding proteins that build and organize specific actin-based structures. Of prime importance are actin nucleators - proteins that stimulate de novo formation of actin filaments. There are three known classes of actin nucleators: the Arp2/3 complex, formins, and tandem WASP homology 2 (WH2) nucleators. Each class nucleates by a distinct mechanism that contributes to the organization of the larger structure being built. Evidence shows that the Arp2/3 complex produces branched actin filaments, remaining bound at the branch point, while formins create linear actin filaments, remaining bound at the growing end. Here, we focus on the formin family of actin nucleators.
Topics: Actin Cytoskeleton; Actin-Related Protein 2-3 Complex; Actins; Formins; Microfilament Proteins
PubMed: 34033783
DOI: 10.1016/j.cub.2021.02.047 -
Trends in Cell Biology Mar 2021Actin plays roles in many important cellular processes, including cell motility, organelle movement, and cell signaling. The discovery of transmembrane actin-binding... (Review)
Review
Actin plays roles in many important cellular processes, including cell motility, organelle movement, and cell signaling. The discovery of transmembrane actin-binding proteins at the outer nuclear membrane (ONM) raises the exciting possibility that actin can play a role in direct force transmission to the nucleus and the genome at its interior. Actin-dependent nucleus displacement was first described a decade ago. We are now gaining a more detailed understanding of its mechanisms, as well as new roles for actin during mitosis and meiosis, for gene expression, and in the cell's response to mechanical stimuli. Here we review these recent developments, the actin-binding proteins involved, the tissue specificity of these mechanisms, and methods developed to reconstitute and study this interaction in vitro.
Topics: Actins; Cell Movement; Cell Nucleus; Microfilament Proteins; Nuclear Envelope
PubMed: 33376040
DOI: 10.1016/j.tcb.2020.11.009 -
Signal Transduction and Targeted Therapy Nov 2023Glioma is the most prevalent brain tumor, presenting with limited treatment options, while patients with malignant glioma and glioblastoma (GBM) have poor prognoses. The...
Glioma is the most prevalent brain tumor, presenting with limited treatment options, while patients with malignant glioma and glioblastoma (GBM) have poor prognoses. The physical obstacle to drug delivery imposed by the blood‒brain barrier (BBB) and glioma stem cells (GSCs), which are widely recognized as crucial elements contributing to the unsatisfactory clinical outcomes. In this study, we found a small molecule, gambogic amide (GA-amide), exhibited the ability to effectively penetrate the blood-brain barrier (BBB) and displayed a notable enrichment within the tumor region. Moreover, GA-amide exhibited significant efficacy in inhibiting tumor growth across various in vivo glioma models, encompassing transgenic and primary patient-derived xenograft (PDX) models. We further performed a genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) knockout screen to determine the druggable target of GA-amide. By the combination of the cellular thermal shift assay (CETSA), the drug affinity responsive target stability (DARTS) approach, molecular docking simulation and surface plasmon resonance (SPR) analysis, WD repeat domain 1 (WDR1) was identified as the direct binding target of GA-amide. Through direct interaction with WDR1, GA-amide promoted the formation of a complex involving WDR1, MYH9 and Cofilin, which accelerate the depolymerization of F-actin to inhibit the invasion of patient-derived glioma cells (PDCs) and induce PDC apoptosis via the mitochondrial apoptotic pathway. In conclusion, our study not only identified GA-amide as an effective and safe agent for treating glioma but also shed light on the underlying mechanisms of GA-amide from the perspective of cytoskeletal homeostasis.
Topics: Humans; Molecular Docking Simulation; Cell Line, Tumor; Glioma; Cytoskeleton; Amides; Microfilament Proteins
PubMed: 37935665
DOI: 10.1038/s41392-023-01666-3 -
Molecular Cancer Jun 2020Lung cancer has high morbidity and mortality worldwide with non-small cell lung cancer (NSCLC) accounting for 85% of the cases. Therapies for lung cancer have relatively...
BACKGROUND
Lung cancer has high morbidity and mortality worldwide with non-small cell lung cancer (NSCLC) accounting for 85% of the cases. Therapies for lung cancer have relatively poor outcomes and further improvements are required. Circular RNAs have been reported to participate in the occurrence and progression of cancer. Information on the functions and mechanism of circRNAs in lung cancer is limited and needs more exploration.
METHODS
We detected expression of genes and proteins by qPCR and western blot. Function of circSATB2 was investigated using RNA interference and overexpression assays. Location of circSATB2 was assessed by fluorescence in situ hybridization (FISH). Interaction of circSATB2, miR-326 and FSCN1 was confirmed by dual-luciferase reporter assay.
RESULTS
Data from the investigation showed that circSATB2 was highly expressed in NSCLC cells and tissues. circSATB2 positively regulated fascin homolog 1, actin-bundling protein 1 (FSCN1) expression via miR-326 in lung cancer cells. Furthermore, circSATB2 can be transferred by exosomes and promote the proliferation, migration and invasion of NSCLC cells, as well as induce abnormal proliferation in normal human bronchial epithelial cells. Also, circSATB2 was highly expressed in serumal exosomes from lung cancer patients with high sensitivity and specificity for clinical detection and was related to lung cancer metastasis.
CONCLUSIONS
circSATB2 participated in the progression of NSCLC and was differentially expressed in lung cancer tissue and serumal exosomes. circSATB2 may be potential biomarker for the diagnosis of NSCLC.
Topics: Apoptosis; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Carrier Proteins; Cell Movement; Cell Proliferation; Disease Progression; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Matrix Attachment Region Binding Proteins; MicroRNAs; Microfilament Proteins; Prognosis; RNA, Circular; Transcription Factors; Tumor Cells, Cultured
PubMed: 32493389
DOI: 10.1186/s12943-020-01221-6 -
Discovery Medicine 2021Actin-binding protein (transgelin, TAGLN) is a kind of protein that regulates actin polymerization, aggregating (or bundling), or cross-linking. As a member of the... (Review)
Review
Actin-binding protein (transgelin, TAGLN) is a kind of protein that regulates actin polymerization, aggregating (or bundling), or cross-linking. As a member of the actin-binding protein complex, transgelin-2 is involved in the regulation of cytoskeleton. Transgelin-2 is widely expressed in various tissues and organs of the body, but its abnormal expression is often seen in all kinds of tumors, which is related to the occurrence and development, and especially the invasion, metastasis, and drug resistance in many kinds of malignant tumors. However, the signal pathway involved in the regulation of transgelin-2 and its mechanism have remained to be elucidated. In recent years, with a more in-depth study of transgelin-2, its relationship with tumorigenesis has become increasingly clear. Therefore, we review recent research progress in transgelin-2, which is helpful to provide ideas for further research and bring forth a new scheme for the diagnosis, treatment, and prognosis of tumors.
Topics: Carcinogenesis; Humans; Microfilament Proteins; Muscle Proteins; Neoplasms
PubMed: 35219353
DOI: No ID Found -
Journal of Experimental & Clinical... Sep 2021Ovarian cancer (OC) progression is an unmet medical challenge. Since omental metastases were palpated harder than their primary counterparts during cytoreductive surgery...
BACKGROUND
Ovarian cancer (OC) progression is an unmet medical challenge. Since omental metastases were palpated harder than their primary counterparts during cytoreductive surgery of patients with epithelial ovarian cancer (EOC), we were inspired to investigate OC progression from the perspective of biomechanics.
METHODS
Atomic Force Microscope (AFM) was used to measure the Young's modulus of tissues. The collagen-coated polyacrylamide hydrogel (PA gel) system was prepared to mimic the soft and stiff substrates in vitro. The effect of TAGLN was evaluated both in vitro and in vivo using transwell assay, immunofluorescence, western blot analysis and immunohistochemistry.
RESULTS
We quantitatively confirmed that omental metastases were stiffer and more abundant in desmoplasia compared with paired primary tumors, and further demonstrated that matrix stiffness could notably regulate OC progression. Remarkably, TAGLN, encoding an actin cross-linking/gelling protein, was identified as a potent mechanosensitive gene that could form a regulation loop with Src activation reacting to environmental stiffness, thus mediating stiffness-regulated OC progression through regulating RhoA/ROCK pathway.
CONCLUSIONS
These data demonstrate that targeting extra-cellular matrix (ECM) stiffness could probably hamper OC progression, and of note, targeting TAGLN might provide promising clinical therapeutic value for OC therapy.
Topics: Animals; Cell Line, Tumor; Disease Models, Animal; Disease Progression; Extracellular Matrix; Female; Fluorescent Antibody Technique; Gene Expression; Gene Expression Profiling; Humans; Mice; Microfilament Proteins; Models, Biological; Muscle Proteins; Neoplasm Metastasis; Ovarian Neoplasms; Prognosis; Signal Transduction; Tumor Microenvironment; rho-Associated Kinases; rhoA GTP-Binding Protein; src-Family Kinases
PubMed: 34538264
DOI: 10.1186/s13046-021-02091-6 -
Cells Nov 2022The heart reacts to a large number of pathological stimuli through cardiac hypertrophy, which finally can lead to heart failure. However, the molecular mechanisms of... (Review)
Review
The heart reacts to a large number of pathological stimuli through cardiac hypertrophy, which finally can lead to heart failure. However, the molecular mechanisms of cardiac hypertrophy remain elusive. Actin participates in the formation of highly differentiated myofibrils under the regulation of actin-binding proteins (ABPs), which provides a structural basis for the contractile function and morphological change in cardiomyocytes. Previous studies have shown that the functional abnormality of ABPs can contribute to cardiac hypertrophy. Here, we review the function of various actin-binding proteins associated with the development of cardiac hypertrophy, which provides more references for the prevention and treatment of cardiomyopathy.
Topics: Humans; Microfilament Proteins; Cardiomegaly; Heart Failure; Myocytes, Cardiac
PubMed: 36428995
DOI: 10.3390/cells11223566 -
Journal of Muscle Research and Cell... Mar 2020The interactions of cytoskeletal actin filaments with myosin family motors are essential for the integrity and function of eukaryotic cells. They support a wide range of... (Review)
Review
The interactions of cytoskeletal actin filaments with myosin family motors are essential for the integrity and function of eukaryotic cells. They support a wide range of force-dependent functions. These include mechano-transduction, directed transcellular transport processes, barrier functions, cytokinesis, and cell migration. Despite the indispensable role of tropomyosins in the generation and maintenance of discrete actomyosin-based structures, the contribution of individual cytoskeletal tropomyosin isoforms to the structural and functional diversification of the actin cytoskeleton remains a work in progress. Here, we review processes that contribute to the dynamic sorting and targeted distribution of tropomyosin isoforms in the formation of discrete actomyosin-based structures in animal cells and their effects on actin-based motility and contractility.
Topics: Actins; Humans; Tropomyosin
PubMed: 31054005
DOI: 10.1007/s10974-019-09514-0 -
Cells Oct 2020The actin cytoskeleton plays a crucial role in many cellular processes while its reorganization is important in maintaining cell homeostasis. However, in the case of... (Review)
Review
The actin cytoskeleton plays a crucial role in many cellular processes while its reorganization is important in maintaining cell homeostasis. However, in the case of cancer cells, actin and ABPs (actin-binding proteins) are involved in all stages of carcinogenesis. Literature has reported that ABPs such as SATB1 (special AT-rich binding protein 1), WASP (Wiskott-Aldrich syndrome protein), nesprin, and villin take part in the initial step of carcinogenesis by regulating oncogene expression. Additionally, changes in actin localization promote cell proliferation by inhibiting apoptosis (SATB1). In turn, migration and invasion of cancer cells are based on the formation of actin-rich protrusions (Arp2/3 complex, filamin A, fascin, α-actinin, and cofilin). Importantly, more and more scientists suggest that microfilaments together with the associated proteins mediate tumor vascularization. Hence, the presented article aims to summarize literature reports in the context of the potential role of actin and ABPs in all steps of carcinogenesis.
Topics: Actins; Carcinogenesis; Cell Movement; Humans; Microfilament Proteins
PubMed: 33036298
DOI: 10.3390/cells9102245