scholarly journals Leep1 interacts with PIP3 and the Scar/WAVE complex to regulate cell migration and macropinocytosis

2021 ◽  
Vol 220 (7) ◽  
Author(s):  
Yihong Yang ◽  
Dong Li ◽  
Xiaoting Chao ◽  
Shashi P. Singh ◽  
Peter Thomason ◽  
...  
Keyword(s):  
Leading Edge ◽  
Cell Types ◽  
Model System ◽  
Cellular Mechanism ◽  
Leucine Rich Repeat ◽  
Repeat Domain ◽  
Full Complement ◽  
Proteomic Screening ◽  
Spatiotemporal Coordination ◽  
Wave Complex

Polarity is essential for diverse functions in many cell types. Establishing polarity requires targeting a network of specific signaling and cytoskeleton molecules to different subregions of the cell, yet the full complement of polarity regulators and how their activities are integrated over space and time to form morphologically and functionally distinct domains remain to be uncovered. Here, by using the model system Dictyostelium and exploiting the characteristic chemoattractant-stimulated translocation of polarly distributed molecules, we developed a proteomic screening approach, through which we identified a leucine-rich repeat domain–containing protein we named Leep1 as a novel polarity regulator. We combined imaging, biochemical, and phenotypic analyses to demonstrate that Leep1 localizes selectively at the leading edge of cells by binding to PIP3, where it modulates pseudopod and macropinocytic cup dynamics by negatively regulating the Scar/WAVE complex. The spatiotemporal coordination of PIP3 signaling, Leep1, and the Scar/WAVE complex provides a cellular mechanism for organizing protrusive structures at the leading edge.

scholarly journals Cytoskeletal Mechanics Regulating Amoeboid Cell Locomotion

2014 ◽  
Vol 66 (5) ◽  
Author(s):  
Begoña Álvarez-González ◽  
Effie Bastounis ◽  
Ruedi Meili ◽  
Juan C. del Álamo ◽  
Richard Firtel ◽  
...  
Keyword(s):  
Cell Migration ◽  
Traction Force ◽  
Leading Edge ◽  
Cell Types ◽  
Traction Forces ◽  
Amoeboid Cell ◽  
Periodic Movement ◽  
Wide Range ◽  
Motility Cycle ◽  
Wave Complex

Migrating cells exert traction forces when moving. Amoeboid cell migration is a common type of cell migration that appears in many physiological and pathological processes and is performed by a wide variety of cell types. Understanding the coupling of the biochemistry and mechanics underlying the process of migration has the potential to guide the development of pharmacological treatment or genetic manipulations to treat a wide range of diseases. The measurement of the spatiotemporal evolution of the traction forces that produce the movement is an important aspect for the characterization of the locomotion mechanics. There are several methods to calculate the traction forces exerted by the cells. Currently the most commonly used ones are traction force microscopy methods based on the measurement of the deformation induced by the cells on elastic substrate on which they are moving. Amoeboid cells migrate by implementing a motility cycle based on the sequential repetition of four phases. In this paper, we review the role that specific cytoskeletal components play in the regulation of the cell migration mechanics. We investigate the role of specific cytoskeletal components regarding the ability of the cells to perform the motility cycle effectively and the generation of traction forces. The actin nucleation in the leading edge of the cell, carried by the ARP2/3 complex activated through the SCAR/WAVE complex, has shown to be fundamental to the execution of the cyclic movement and to the generation of the traction forces. The protein PIR121, a member of the SCAR/WAVE complex, is essential to the proper regulation of the periodic movement and the protein SCAR, also included in the SCAR/WAVE complex, is necessary for the generation of the traction forces during migration. The protein Myosin II, an important F-actin cross-linker and motor protein, is essential to cytoskeletal contractility and to the generation and proper organization of the traction forces during migration.

Nanotopography-Modulated Epithelial Cell Collective Migration

2021 ◽  
Vol 17 (6) ◽  
pp. 1079-1087
Author(s):  
Zaozao Chen ◽  
Qiwei Li ◽  
Shihui Xu ◽  
Jun Ouyang ◽  
Hongmei Wei
Keyword(s):  
Wound Healing ◽  
Cell Migration ◽  
Epithelial Cells ◽  
Leading Edge ◽  
Cell Types ◽  
Protein Kinase Activity ◽  
Migration Behavior ◽  
Collective Migration ◽  
Epithelial Migration ◽  
Activity Dependent

Matrix nanotopography plays an essential role in regulating cell behaviors including cell proliferation, differentiation, and migration. While studies on isolated single cell migration along the nanostructural orientation have been reported for various cell types, there remains a lack of understanding of how nanotopography regulates the behavior of collectively migrating cells during processes such as epithelial wound healing. We demonstrated that collective migration of epithelial cells was promoted on nanogratings perpendicular to, but not on those parallel to, the wound-healing axis. We further discovered that nanograting-modulated epithelial migration was dominated by the adhesion turnover process, which was Rho-associated protein kinase activity-dependent, and the lamellipodia protrusion at the cell leading edge, which was Rac1-GTPase activity-dependent. This work provides explanations to the distinct migration behavior of epithelial cells on nanogratings, and indicates that the effect of nanotopographic modulations on cell migration is cell-type dependent and involves complex mechanisms

scholarly journals Dynactin is required for bidirectional organelle transport

2003 ◽  
Vol 160 (3) ◽  
pp. 297-301 ◽  
Author(s):  
Sean W. Deacon ◽  
Anna S. Serpinskaya ◽  
Patricia S. Vaughan ◽  
Monica Lopez Fanarraga ◽  
Isabelle Vernos ◽  
...  
Keyword(s):  
Cell Types ◽  
Cytoplasmic Dynein ◽  
Opposite Polarity ◽  
Model System ◽  
Organelle Transport ◽  
Transport Activity ◽  
Microtubule Motors ◽  
Microtubule Motor ◽  
Dynactin Complex ◽  
Binding Subunit

Kinesin II is a heterotrimeric plus end–directed microtubule motor responsible for the anterograde movement of organelles in various cell types. Despite substantial literature concerning the types of organelles that kinesin II transports, the question of how this motor associates with cargo organelles remains unanswered. To address this question, we have used Xenopus laevis melanophores as a model system. Through analysis of kinesin II–mediated melanosome motility, we have determined that the dynactin complex, known as an anchor for cytoplasmic dynein, also links kinesin II to organelles. Biochemical data demonstrates that the putative cargo-binding subunit of Xenopus kinesin II, Xenopus kinesin II–associated protein (XKAP), binds directly to the p150Glued subunit of dynactin. This interaction occurs through aa 530–793 of XKAP and aa 600–811 of p150Glued. These results reveal that dynactin is required for transport activity of microtubule motors of opposite polarity, cytoplasmic dynein and kinesin II, and may provide a new mechanism to coordinate their activities.

scholarly journals The evolution of the metazoan Toll receptor family and its expression during protostome development

2021 ◽  
Author(s):  
Andrea Orús-Alcalde ◽  
Tsai-Ming Lu ◽  
Andreas Hejnol
Keyword(s):  
Phylogenetic Analysis ◽  
Transmembrane Domain ◽  
Leucine Rich Repeat ◽  
Animal Development ◽  
Phylogenetic Studies ◽  
Repeat Domain ◽  
Toll Receptor ◽  
P Type

Abstract Background: Toll-like receptors (TLRs) play a crucial role in immunity and development. They contain leucine-rich repeat domains, one transmembrane domain, and one Toll/IL-1 receptor domain. TLRs have been classified into V-type/scc and P-type/mcc TLRs, based on differences in the leucine-rich repeat domain region. Although TLRs are widespread in animals, detailed phylogenetic studies of this gene family are lacking. Here we aim to uncover TLR evolution by conducting a survey and a phylogenetic analysis in species across Bilateria. To discriminate between their role in development and immunity we furthermore analyzed stage-specific transcriptomes of the ecdysozoans Priapulus caudatus and Hypsibius exemplaris, and the spiralians Crassostrea gigas and Terebratalia transversa.Results: We detected a low number of TLRs in ecdysozoan species, and multiple independent radiations within the Spiralia. V-type/scc and P-type/mcc type-receptors are present in cnidarians, protostomes and deuterostomes, and therefore they emerged early in TLR evolution, followed by a loss in xenacoelomorphs. Our phylogenetic analysis shows that TLRs cluster into three major clades: clade α is present in cnidarians, ecdysozoans, and spiralians; clade β in deuterostomes, ecdysozoans, and spiralians; and clade γ is only found in spiralians. Our stage-specific transcriptome and in situ hybridization analyses show that TLRs are expressed during development in all species analyzed, which indicates a broad role of TLRs during animal development.Conclusions: Our findings suggest that the bilaterian TLRs likely emerged by duplication from a single TLR encoding gene (proto-TLR) present in the last common cnidarian-bilaterian ancestor. This proto-TLR gene duplicated before the split of protostomes and deuterostomes; a second duplication occurred in the lineage to the Trochozoa. While all three clades further radiated in several spiralian lineages, specific TLRs clades have been presumably lost in others. Furthermore, the expression of the majority of these genes during protostome ontogeny suggests their involvement in immunity and development.

scholarly journals Characterisation of GLUT4 trafficking in HeLa cells: comparable kinetics and orthologous trafficking mechanisms to 3T3-L1 adipocytes

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8751 ◽  
Author(s):  
Silke Morris ◽  
Niall D. Geoghegan ◽  
Jessica B.A. Sadler ◽  
Anna M. Koester ◽  
Hannah L. Black ◽  
...  
Keyword(s):  
Cell Surface ◽  
Hela Cells ◽  
Glucose Transporter ◽  
Characteristic Property ◽  
Cell Types ◽  
Model System ◽  
Human Model ◽  
Small Scale ◽  
Glucose Transporter Glut4 ◽  
Surface Fusion

Insulin-stimulated glucose transport is a characteristic property of adipocytes and muscle cells and involves the regulated delivery of glucose transporter (GLUT4)-containing vesicles from intracellular stores to the cell surface. Fusion of these vesicles results in increased numbers of GLUT4 molecules at the cell surface. In an attempt to overcome some of the limitations associated with both primary and cultured adipocytes, we expressed an epitope- and GFP-tagged version of GLUT4 (HA–GLUT4–GFP) in HeLa cells. Here we report the characterisation of this system compared to 3T3-L1 adipocytes. We show that insulin promotes translocation of HA–GLUT4–GFP to the surface of both cell types with similar kinetics using orthologous trafficking machinery. While the magnitude of the insulin-stimulated translocation of GLUT4 is smaller than mouse 3T3-L1 adipocytes, HeLa cells offer a useful, experimentally tractable, human model system. Here, we exemplify their utility through a small-scale siRNA screen to identify GOSR1 and YKT6 as potential novel regulators of GLUT4 trafficking in human cells.

The developmentally regulated ECM glycoprotein ISG plays an essential role in organizing the ECM and orienting the cells of Volvox

2000 ◽  
Vol 113 (24) ◽  
pp. 4605-4617
Author(s):  
A. Hallmann ◽  
D.L. Kirk
Keyword(s):  
Critical Role ◽  
Somatic Cells ◽  
Cell Types ◽  
Model System ◽  
Swimming Behavior ◽  
Truncated Form ◽  
Developmentally Regulated ◽  
Gene Encoding ◽  
Ecm Architecture ◽  
Multicellular Organisms

Volvox is one of the simplest multicellular organisms with only two cell types, yet it has a surprisingly complex extracellular matrix (ECM) containing many region-specific morphological components, making Volvox suitable as a model system for ECM investigations. ECM deposition begins shortly after inversion, which is the process by which the embryo turns itself right-side-out at the end of embryogenesis. It was previously shown that the gene encoding an ECM glycoprotein called ISG is transcribed very transiently during inversion. Here we show that the developmentally controlled ISG accumulates at the bases of the flagella right after inversion, before any morphologically recognizable ECM structures have yet developed. Later, ISG is abundant in the ‘flagellar hillocks’ that encircle the basal ends of all flagella, and in the adjacent ‘boundary zone’ that delimits the spheroid. Transgenic Volvox were generated which express a truncated form of ISG. These transgenics exhibit a severely disorganized ECM within which the cells are embedded in a highly chaotic manner that precludes motility. A synthetic version of the C-terminal decapeptide of ISG has a similar disorganizing effect, but only when it is applied during or shortly after inversion. We postulate that ISG plays a critical role in morphogenesis and acts as a key organizer of ECM architecture; at the very beginning of ECM formation ISG establishes an essential initial framework that both holds the somatic cells in an adaptive orientation and acts as the scaffold upon which the rest of the ECM can be properly assembled, assuring that somatic cells of post-inversion spheroids are held in orientations and locations that makes adaptive swimming behavior possible.

scholarly journals Clinical characterization, genetic profiling, and immune infiltration of TOX in diffuse gliomas

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Hao Zhang ◽  
Fan Fan ◽  
Yuanqiang Yu ◽  
Zeyu Wang ◽  
Fangkun Liu ◽  
...  
Keyword(s):  
Immune Cell ◽  
Malignant Gliomas ◽  
Leading Edge ◽  
Cell Types ◽  
Tumour Microenvironment ◽  
The Cancer Genome Atlas ◽  
Low Grade ◽  
Lymphocyte Migration ◽  
Who Grade ◽  
Genome Atlas

Abstract Background Immunotherapies targeting glioblastoma (GBM) have led to significant improvements in patient outcomes. TOX is closely associated with the immune environment surrounding tumors, but its role in gliomas is not fully understood. Methods Using data from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA), we analyzed the transcriptomes of 1691 WHO grade I-IV human glioma samples. The R language was used to perform most of the statistical analyses. Somatic mutations and somatic copy number variation (CNV) were analyzed using GISTIC 2.0. Results TOX was down-regulated in malignant gliomas compared to low grade gliomas, and upregulated in the proneural and IDH mutant subtypes of GBM. TOXlow tumours are associated with the loss of PTEN and amplification of EGFR, while TOXhigh tumours harbor frequent mutations in IDH1 (91%). TOX was highly expressed in leading edge regions of tumours. Gene ontology and pathway analyses demonstrated that TOX was enriched in multiple immune related processes including lymphocyte migration in GBM. Finally, TOX had a negative association with the infiltration of several immune cell types in the tumour microenvironment. Conclusion TOX has the potential to be a new prognostic marker for GBM.

scholarly journals Sequential ubiquitination of NLRP3 by RNF125 and Cbl-b limits inflammasome activation and endotoxemia

2020 ◽  
Vol 217 (4) ◽  
Author(s):  
Juan Tang ◽  
Sha Tu ◽  
Guoxin Lin ◽  
Hui Guo ◽  
Chengkai Yan ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Lethal Dose ◽  
E3 Ubiquitin Ligase ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Leucine Rich Repeat ◽  
Nlrp3 Inflammasome Activation ◽  
Repeat Domain ◽  
Nlrp3 Inflammasomes ◽  
Lrr Domain

Aberrant NLRP3 inflammasome activation contributes to the development of endotoxemia. The importance of negative regulation of NLRP3 inflammasomes remains poorly understood. Here, we show that the E3 ubiquitin ligase Cbl-b is essential for preventing endotoxemia induced by a sub-lethal dose of LPS via a caspase-11/NLRP3–dependent manner. Further studies show that NLRP3 undergoes both K63- and K48-linked polyubiquitination. Cbl-b binds to the K63-ubiquitin chains attached to the NLRP3 leucine-rich repeat domain (LRR) via its ubiquitin-associated region (UBA) and then targets NLRP3 at K496 for K48-linked ubiquitination and proteasome-mediated degradation. We also identify RNF125 as an additional E3 ubiquitin ligase that initiates K63-linked ubiquitination of the NLRP3 LRR domain. Therefore, NLRP3 is sequentially ubiquitinated by K63- and K48-linked ubiquitination, thus keeping the NLRP3 inflammasomes in check and restraining endotoxemia.

Methylation and expression of the Myo D1 determination gene

1990 ◽  
Vol 326 (1235) ◽  
pp. 277-284 ◽  
Keyword(s):  
De Novo ◽  
Cell Types ◽  
Model System ◽  
Parental Line ◽  
Molecular Control ◽  
Embryo Cells ◽  
End Stage ◽  
Derivatives Of

Mouse embryo cells induced to differentiate with the demethylating agent 5- azacytidine represent an excellent model system to investigate the molecular control of development. Clonal derivatives of 10T1/2 cells that have become determined to the myogenic or adipogenic lineages can be isolated from the multipotential parental line after drug treatment. These determined derivatives can be cultured indefinitely and will differentiate into end-stage phenotypes on appropriate stimulation. A gene called Myo D1, recently isolated from such a myoblast line, will confer myogenesis when expressed in 10T1/2 or other cell types (Davis et al. 1987). The cDNA for Myo D1 contains a large number of CpG sequences and the gene is relatively methylated in 10T1/2 cells and an adipocyte derivative, but is demethylated in myogenic derivatives. Myo D1 may therefore be subject to methylation control in vitro . On the other hand, preliminary observations suggest that Myo D1 is not methylated at CCGG sites in vivo so that a de novo methylation event may have occurred in vitro . These observations may have significance in the establishment of immortal cell lines and tumours.

Phosphoinositide lipids and cell polarity: linking the plasma membrane to the cytocortex

2012 ◽  
Vol 53 ◽  
pp. 15-27 ◽  
Author(s):  
Michael P. Krahn ◽  
Andreas Wodarz
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Membrane Lipids ◽  
Leading Edge ◽  
Cell Types ◽  
Specific Protein ◽  
Molecular Organization ◽  
Apical Side ◽  
Cell Substrate ◽  
Basolateral Side

Many cell types in animals and plants are polarized, which means that the cell is subdivided into functionally and structurally distinct compartments. Epithelial cells, for example, possess an apical side facing a lumen or the outside environment and a basolateral side facing adjacent epithelial cells and the basement membrane. Neurons possess distinct axonal and dendritic compartments with specific functions in sending and receiving signals. Migrating cells form a leading edge that actively engages in pathfinding and cell-substrate attachment, and a trailing edge where such attachments are abandoned. In all of these cases, both the plasma membrane and the cytocortex directly underneath the plasma membrane show differences in their molecular composition and structural organization. In this chapter we will focus on a specific type of membrane lipids, the phosphoinositides, because in polarized cells they show a polarized distribution in the plasma membrane. They furthermore influence the molecular organization of the cytocortex by recruiting specific protein binding partners which are involved in the regulation of the cytoskeleton and in signal transduction cascades that control polarity, growth and cell migration.

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