scholarly journals The actin regulators Enabled and Diaphanous direct distinct protrusive behaviors in different tissues during Drosophila development

2014 ◽  
Vol 25 (20) ◽  
pp. 3147-3165 ◽  
Author(s):  
Stephanie H. Nowotarski ◽  
Natalie McKeon ◽  
Rachel J. Moser ◽  
Mark Peifer
Keyword(s):  
Actin Polymerization ◽  
Cultured Cells ◽  
Leading Edge ◽  
Dorsal Closure ◽  
Primary Role ◽  
Loss Of Function ◽  
Timely Completion ◽  
And Migration ◽  
Different Tissues

Actin-based protrusions are important for signaling and migration during development and homeostasis. Defining how different tissues in vivo craft diverse protrusive behaviors using the same genomic toolkit of actin regulators is a current challenge. The actin elongation factors Diaphanous and Enabled both promote barbed-end actin polymerization and can stimulate filopodia in cultured cells. However, redundancy in mammals and Diaphanous’ role in cytokinesis limited analysis of whether and how they regulate protrusions during development. We used two tissues driving Drosophila dorsal closure—migratory leading-edge (LE) and nonmigratory amnioserosal (AS) cells—as models to define how cells shape distinct protrusions during morphogenesis. We found that nonmigratory AS cells produce filopodia that are morphologically and dynamically distinct from those of LE cells. We hypothesized that differing Enabled and/or Diaphanous activity drives these differences. Combining gain- and loss-of-function with quantitative approaches revealed that Diaphanous and Enabled each regulate filopodial behavior in vivo and defined a quantitative “fingerprint”—the protrusive profile—which our data suggest is characteristic of each actin regulator. Our data suggest that LE protrusiveness is primarily Enabled driven, whereas Diaphanous plays the primary role in the AS, and reveal each has roles in dorsal closure, but its robustness ensures timely completion in their absence.

scholarly journals The Arf-GEF Steppke promotes F-actin accumulation, cell protrusions and tissue sealing during Drosophila dorsal closure

2020 ◽  
Author(s):  
Junior J. West ◽  
Tony J. C. Harris
Keyword(s):  
Actin Polymerization ◽  
Cultured Cells ◽  
Genetic Interaction ◽  
Coiled Coil ◽  
Leading Edge ◽  
Cell Junctions ◽  
Drosophila Embryo ◽  
Dorsal Closure ◽  
Ph Domain ◽  
Actin Networks

AbstractCytohesin Arf-GEFs promote actin polymerization and protrusions of cultured cells, whereas the Drosophila cytohesin, Steppke, antagonizes actomyosin networks in several developmental contexts. To reconcile these findings, we analyzed epidermal leading edge actin networks during Drosophila embryo dorsal closure. Here, Steppke is required for F-actin of the actomyosin cable and for actin-based protrusions. steppke mutant defects in the leading edge actin networks are associated with improper sealing of the dorsal midline, but are distinguishable from effects of myosin mis-regulation. Steppke localizes to leading edge cell-cell junctions with accumulations of the F-actin regulator Enabled emanating from either side. Enabled requires Steppke for full leading edge recruitment, and genetic interaction shows the proteins cooperate for dorsal closure. Steppke over-expression induces ectopic, actin-rich, lamellar cell protrusions, an effect dependent on the Arf-GEF activity and PH domain of Steppke, but independent of Steppke recruitment to myosin-rich AJs via its coiled-coil domain. Thus, Steppke promotes actin polymerization and cell protrusions, effects that occur in conjunction with Steppke’s previously reported regulation of myosin contractility during dorsal closure.

scholarly journals The Arf-GEF Steppke promotes F-actin accumulation, cell protrusions and tissue sealing during Drosophila dorsal closure

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0239357
Author(s):  
Junior J. West ◽  
Tony J. C. Harris
Keyword(s):  
Actin Polymerization ◽  
Cultured Cells ◽  
Genetic Interaction ◽  
Coiled Coil ◽  
Leading Edge ◽  
Cell Junctions ◽  
Dorsal Closure ◽  
Ph Domain ◽  
Dorsal Midline ◽  
Actin Networks

Cytohesin Arf-GEFs promote actin polymerization and protrusions of cultured cells, whereas the Drosophila cytohesin, Steppke, antagonizes actomyosin networks in several developmental contexts. To reconcile these findings, we analyzed epidermal leading edge actin networks during Drosophila embryo dorsal closure. Here, Steppke is required for F-actin of the actomyosin cable and for actin-based protrusions. steppke mutant defects in the leading edge actin networks are associated with improper sealing of the dorsal midline, but are distinguishable from effects of myosin mis-regulation. Steppke localizes to leading edge cell-cell junctions with accumulations of the F-actin regulator Enabled emanating from either side. Enabled requires Steppke for full leading edge recruitment, and genetic interaction shows the proteins cooperate for dorsal closure. Inversely, Steppke over-expression induces ectopic, actin-rich, lamellar cell protrusions, an effect dependent on the Arf-GEF activity and PH domain of Steppke, but independent of Steppke recruitment to myosin-rich AJs via its coiled-coil domain. Thus, Steppke promotes actin polymerization and cell protrusions, effects that occur in conjunction with Steppke’s previously reported regulation of myosin contractility during dorsal closure.

scholarly journals CaM kinase IIδ2-dependent regulation of vascular smooth muscle cell polarization and migration

2008 ◽  
Vol 294 (6) ◽  
pp. C1465-C1475 ◽  
Author(s):  
Melissa Z. Mercure ◽  
Roman Ginnan ◽  
Harold A. Singer
Keyword(s):  
Smooth Muscle ◽  
Cell Migration ◽  
Vascular Smooth Muscle ◽  
Cell Monolayer ◽  
Leading Edge ◽  
Cell Polarization ◽  
Loss Of Function ◽  
Downstream Signaling ◽  
Transient Activation ◽  
And Migration

Previous studies indicate involvement of the multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII) in vascular smooth muscle (VSM) cell migration. In the present study, molecular loss-of-function studies were used specifically to assess the role of the predominant CaMKIIδ2 isoform on VSM cell migration using a scratch wound healing assay. Targeted CaMKIIδ2 knockdown using siRNA or inhibition of activity by overexpressing a kinase-negative mutant resulted in attenuation of VSM cell migration. Temporal and spatial assessments of kinase autophosphorylation indicated rapid and transient activation in response to wounding, in addition to a sustained activation in the leading edge of migrating and spreading cells. Furthermore, siRNA-mediated suppression of CaMKIIδ2 resulted in the inhibition of wound-induced Rac activation and Golgi reorganization, and disruption of leading edge morphology, indicating an important function for CaMKIIδ2 in regulating VSM cell polarization. Numerous previous reports link activation of CaMKII to ERK1/2 signaling in VSM. Wound-induced ERK1/2 activation was also found to be dependent on CaMKII; however, ERK activity did not account for effects of CaMKII in regulating Golgi polarization, indicating alternative mechanisms by which CaMKII affects the complex events involved in cell migration. Wounding a VSM cell monolayer results in CaMKIIδ2 activation, which positively regulates VSM cell polarization and downstream signaling, including Rac and ERK1/2 activation, leading to cell migration.

scholarly journals LncRNA GAPLINC Promotes Renal Cell Cancer Tumorigenesis by Targeting the miR-135b-5p/CSF1 Axis

2021 ◽  
Vol 11 ◽  
Author(s):  
Siyuan Wang ◽  
Xiaorong Yang ◽  
Wenjie Xie ◽  
Shengqiang Fu ◽  
Qiang Chen ◽  
...  
Keyword(s):  
Renal Cell ◽  
Noncoding Rna ◽  
Cell Cancer ◽  
Luciferase Reporter ◽  
Loss Of Function ◽  
Long Intergenic Noncoding Rna ◽  
And Migration ◽  
Molecular Therapeutic

BackgroundLong noncoding RNAs (lncRNAs) are closely related to the occurrence and development of cancer. Gastric adenocarcinoma-associated, positive CD44 regulator, long intergenic noncoding RNA (GAPLINC) is a recently identified lncRNA that can actively participate in the tumorigenesis of various cancers. Here, we investigated the functional roles and mechanism of GAPLINC in renal cell carcinoma (RCC) development.MethodsDifferentially expressed lncRNAs between RCC tissues and normal kidney tissues were detected by using a microarray technique. RNA sequencing was applied to explore the mRNA expression profile changes after GAPLINC silencing. After gain- and loss-of-function approaches were implemented, the effect of GAPLINC on RCC in vitro and in vivo was assessed by cell proliferation and migration assays. Moreover, rescue experiments and luciferase reporter assays were used to study the interactions between GAPLINC, miR-135b-5p and CSF1.ResultsGAPLINC was significantly upregulated in RCC tissues and cell lines and was associated with a poor prognosis in RCC patients. Knockdown of GAPLINC repressed RCC growth in vitro and in vivo, while overexpression of GAPLINC exhibited the opposite effect. Mechanistically, we found that GAPLINC upregulates oncogene CSF1 expression by acting as a sponge of miR-135b-5p.ConclusionTaken together, our results suggest that GAPLINC is a novel prognostic marker and molecular therapeutic target for RCC.

scholarly journals Scribble, Lgl1, and myosin II form a complex in vivo to promote directed cell migration

2020 ◽  
Vol 31 (20) ◽  
pp. 2234-2248
Author(s):  
Maha Abedrabbo ◽  
Shoshana Ravid
Keyword(s):  
Cell Migration ◽  
Cell Adhesion ◽  
Myosin Ii ◽  
Leading Edge ◽  
Directed Cell Migration ◽  
Lethal Giant Larvae ◽  
And Migration ◽  
Migrating Cells

Here we show that Scribble (Scrib), Lethal giant larvae 1 (Lgl1), and myosin II form a complex in vivo and colocalize at the cell leading edge of migrating cells, and this colocalization is interdependent. Scrib and Lgl1 are required for proper cell adhesion, polarity, and migration.

scholarly journals Contact guidance requires spatial control of leading-edge protrusion

2017 ◽  
Vol 28 (8) ◽  
pp. 1043-1053 ◽  
Author(s):  
G. R. Ramirez-San Juan ◽  
P. W. Oakes ◽  
M. L. Gardel
Keyword(s):  
Cell Shape ◽  
Spatial Organization ◽  
Leading Edge ◽  
Contact Guidance ◽  
Spatial Constraints ◽  
Migration Direction ◽  
Line Spacing ◽  
Geometric Cues ◽  
And Migration

In vivo, geometric cues from the extracellular matrix (ECM) are critical for the regulation of cell shape, adhesion, and migration. During contact guidance, the fibrillar architecture of the ECM promotes an elongated cell shape and migration along the fibrils. The subcellular mechanisms by which cells sense ECM geometry and translate it into changes in shape and migration direction are not understood. Here we pattern linear fibronectin features to mimic fibrillar ECM and elucidate the mechanisms of contact guidance. By systematically varying patterned line spacing, we show that a 2-μm spacing is sufficient to promote cell shape elongation and migration parallel to the ECM, or contact guidance. As line spacing is increased, contact guidance increases without affecting migration speed. To elucidate the subcellular mechanisms of contact guidance, we analyze quantitatively protrusion dynamics and find that the structured ECM orients cellular protrusions parallel to the ECM. This spatial organization of protrusion relies on myosin II contractility, and feedback between adhesion and Rac-mediated protrusive activity, such that we find Arp2/3 inhibition can promote contact guidance. Together our data support a model for contact guidance in which the ECM enforces spatial constraints on the lamellipodia that result in cell shape elongation and enforce migration direction.

Small-Molecule Screen Identifies ROS as Key Regulators of Actin Dynamics in Neutrophils

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4641-4641
Author(s):  
Hidenori Hattori ◽  
Kulandayan K Subramanian ◽  
Hongbo R. Luo
Keyword(s):  
Small Molecule ◽  
Actin Polymerization ◽  
Neutrophil Migration ◽  
Physiological Role ◽  
Leading Edge ◽  
Actin Dynamics ◽  
Functional Screening ◽  
Cellular Processes

Abstract Precise spatial and temporal control of actin polymerization and depolymerization is essential for mediating various cellular processes such as migration, phagocytosis, vesicle trafficking and adhesion. In this study, we used a small-molecule functional screening approach to identify novel regulators of actin dynamics during neutrophil migration. Here we show that NADPH-oxidase dependent Reactive Oxygen Species act as negative regulators of actin polymerization. Neutrophils with pharmacologically inhibited oxidase or isolated from Chronic Granulomatous Disease (CGD) patient and mice displayed enhanced F-actin polymerization, multiple pseudopods formation and impaired chemotaxis. ROS localized to pseudopodia and inhibited actin polymerization by driving actin glutathionylation at the leading edge of migrating cells. Consistent with these in vitro results, adoptively transferred CGD murine neutrophils also showed impaired in vivo recruitment to sites of inflammation. Together, these results present a novel physiological role for ROS in regulation of action polymerization and shed new light on the pathogenesis of CGD.

scholarly journals ATF2-Induced Overexpression of lncRNA LINC00882, as a Novel Therapeutic Target, Accelerates Hepatocellular Carcinoma Progression via Sponging miR-214-3p to Upregulate CENPM

2021 ◽  
Vol 11 ◽  
Author(s):  
Hua Ren ◽  
Zhi-cheng Wei ◽  
Yan-xia Sun ◽  
Chun-yan Qiu ◽  
Wen-jue Zhang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Promoter Region ◽  
Tumor Xenograft ◽  
Luciferase Reporter ◽  
Loss Of Function ◽  
Protein Coding ◽  
Invasion And Migration ◽  
And Migration ◽  
Hcc Cells

BackgroundLong intergenic non-protein coding RNA 882 (LINC00882) are abnormally expressed in several tumors. Our research aimed to uncover the functions and the potential mechanisms of LINC00882 in hepatocellular carcinoma (HCC) progression.MethodsRT-qPCR was applied to identify LINC00882 and miR-214-3p levels in HCC specimens and cells. Luciferase reporter was applied for the exploration of whether activating transcription factor 2 (ATF2) could bind to the promoter region of LINC00882. Cell proliferation, invasion, and migration were evaluated. In vivo tumor xenograft models were constructed to assess tumorigenicity. RT-PCR, Western blot and Luciferase reporter assays were conducted to examine the regulatory relationships among LINC00882, miR-214-3p and ATF2.ResultsLINC00882 was markedly upregulated in HCC cells and clinical specimens. Additionally, ATF2 could bind directly to the LINC00882 promoter region and activate its transcription. Loss-of-function studies further demonstrated that LINC00882 knockdown inhibited proliferation, invasion, and migration of HCC cells. Mechanistically, LINC00882 adsorbed miR-214-3p, thus promoting the expressions of CENPM. Rescue assays demonstrated that functions of LINC00882 deficiency in HCC cells were reversed through suppressing miR-214-3p.ConclusionOur group identified a novel regulatory axis of ATF2/LINC00882/miR-214-3p/CENPM, which may provide potential therapeutic targets for HCC.

scholarly journals Cytoplasmic dynamics of myosin IIA and IIB: spatial ‘sorting’ of isoforms in locomoting cells

1998 ◽  
Vol 111 (15) ◽  
pp. 2085-2095 ◽  
Author(s):  
J. Kolega
Keyword(s):  
Cultured Cells ◽  
Myosin Ii ◽  
Cell Movement ◽  
Leading Edge ◽  
Time Lapse ◽  
Living Cells ◽  
Immunofluorescence Staining ◽  
Spatial Sorting ◽  
Time Lapse Imaging

Different isoforms of non-muscle myosin II have different distributions in vivo, even within individual cells. In order to understand how these different distributions arise, the distribution and dynamics of non-muscle myosins IIA and myosin IIB were examined in cultured cells using immunofluorescence staining and time-lapse imaging of fluorescent analogs. Cultured bovine aortic endothelia contained both myosins IIA and IIB. Both isoforms distributed along stress fibers, in linear or punctate aggregates within lamellipodia, and diffusely around the nucleus. However, the A isoform was preferentially located toward the leading edge of migrating cells when compared with myosin IIB by double immunofluorescence staining. Conversely, the B isoform was enriched in structures at the cells' trailing edges. When fluorescent analogs of the two isoforms were co-injected into living cells, the injected myosins distributed with the same disparate localizations as endogenous myosins IIA and IIB. This indicated that the ability of the myosins to ‘sort’ within the cytoplasm is intrinsic to the proteins themselves, and not a result of localized synthesis or degradation. Furthermore, time-lapse imaging of injected analogs in living cells revealed differences in the rates at which the two isoforms rearranged during cell movement. The A isoform appeared in newly formed structures more rapidly than the B isoform, and was also lost more rapidly when structures disassembled. These observations suggest that the different localizations of myosins IIA and IIB reflect different rates at which the isoforms transit through assembly, movement and disassembly within the cell. The relative proportions of different myosin II isoforms within a particular cell type may determine the lifetimes of various myosin II-based structures in that cell.

scholarly journals Murine Surf4 is essential for early embryonic development

2019 ◽  
Author(s):  
Brian T. Emmer ◽  
Paul J. Lascuna ◽  
Emilee N. Kotnik ◽  
Thomas L. Saunders ◽  
Rami Khoriaty ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Apolipoprotein B ◽  
Gene Editing ◽  
Cultured Cells ◽  
Early Embryonic Development ◽  
Loss Of Function ◽  
Normal Appearance ◽  
Anterograde Transport ◽  
Transport Vesicles

ABSTRACTNewly synthesized proteins co-translationally inserted into the endoplasmic reticulum (ER) lumen may be recruited into anterograde transport vesicles by their association with specific cargo receptors. We recently identified a role for the cargo receptor SURF4 in facilitating the secretion of PCSK9 in cultured cells. To examine the function of SURF4 in vivo, we used CRISPR/Cas9-mediated gene editing to generate mice with germline loss-of-function mutations in Surf4. Surf4+/- mice exhibited grossly normal appearance, behavior, body weight, fecundity, and organ development and demonstrated no significant alterations in circulating plasma levels of PCSK9, apolipoprotein B, or total cholesterol. Surf4-/- mice exhibit embryonic lethality, with complete loss of all Surf4-/- offspring between embryonic days 3.5 and 9.5. Taken together with the much milder phenotypes of PCSK9 or apolipoprotein B deficiency in mice, these findings imply the existence of additional SURF4 cargoes or functions that are essential for murine early embryonic development.

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