Dynamic control of cell-cell adhesion and membrane-associated actin during food-induced mouth opening in Beroe

1993 ◽  
Vol 106 (1) ◽  
pp. 355-364
Author(s):  
S.L. Tamm ◽  
S. Tamm
Keyword(s):  
Cell Adhesion ◽  
Actin Cytoskeleton ◽  
Actin Filaments ◽  
Dynamic Control ◽  
Mouth Opening ◽  
Cell Junctions ◽  
Dynamic Changes ◽  
Rhodamine Phalloidin ◽  
Rapid Changes ◽  
Muscular Action

We used rhodamine-phalloidin and ultrastructural methods to follow dynamic changes in adhesive cell junctions and associated actin filaments during reversible epithelial adhesion in the mouth of the ctenophore Beroe. A cruising Beroe keeps its mouth closed by interdigitated actin-coated appositions between paired strips of cells lining the lips. The mouth opens rapidly (in 0.2-0.3 s) by muscular action to engulf prey (other ctenophores), then re-seals after ingestion. We found that the interlocking surface architecture of the adhesive cells, including the actin-coated junctions, rapidly disappears after food-induced opening of the mouth. In contrast, forcible separation of the lips in the absence of food rips the junctions, still intact, from the surfaces of the cells. The prey-stimulated loss of adhesive cell junctions and associated actin cytoskeleton is one of the most rapid changes in actin-based junctions yet observed. This system provides unique experimental advantages for investigating the dynamic control of reversible cell adhesions and membrane-associated actin filaments.

scholarly journals Revolving movement of a dynamic cluster of actin filaments during mitosis

2010 ◽  
Vol 191 (3) ◽  
pp. 453-462 ◽  
Author(s):  
Masaru Mitsushima ◽  
Kazuhiro Aoki ◽  
Miki Ebisuya ◽  
Shigeru Matsumura ◽  
Takuya Yamamoto ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Filaments ◽  
Angular Speed ◽  
Cell Cortex ◽  
Actin Assembly ◽  
Contractile Ring ◽  
Dynamic Cluster ◽  
Rapid Changes ◽  
M Phase ◽  
Key Factor

The actin cytoskeleton undergoes rapid changes in its architecture during mitosis. Here, we demonstrate novel actin assembly dynamics in M phase. An amorphous cluster of actin filaments appears during prometaphase, revolves horizontally along the cell cortex at a constant angular speed, and fuses into the contractile ring after three to four revolutions. Cdk1 activity is required for the formation of this mitotic actin cluster and its revolving movement. Rapid turnover of actin in the filaments takes place everywhere in the cluster and is also required for its cluster rotation during mitosis. Knockdown of Arp3, a component of the actin filament–nucleating Arp2/3 complex, inhibits the formation of the mitotic actin cluster without affecting other actin structures. These results identify Arp2/3 complex as a key factor in the generation of the dynamic actin cluster during mitosis.

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

The Drosophila AIP orthologue is essential for actin cytoskeleton stabilisation and cell adhesion

2016 ◽  
Author(s):  
Elena Daniela Aflorei ◽  
Benjamin Klapholz ◽  
Nina Moderau ◽  
Paulo Baptista-Ribeiro ◽  
Nic Tapon ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Actin Cytoskeleton

scholarly journals Two Sides of the Coin: Ezrin/Radixin/Moesin and Merlin Control Membrane Structure and Contact Inhibition

2019 ◽  
Vol 20 (8) ◽  
pp. 1996 ◽  
Author(s):  
Katharine A. Michie ◽  
Adam Bermeister ◽  
Neil O. Robertson ◽  
Sophia C. Goodchild ◽  
Paul M. G. Curmi
Keyword(s):  
Actin Cytoskeleton ◽  
Protein Complexes ◽  
Membrane Vesicle ◽  
Contact Inhibition ◽  
Cell Junctions ◽  
Cellular Membranes ◽  
Membrane Structures ◽  
Cortical Actin ◽  
Erm Proteins ◽  
Structural Conservation

The merlin-ERM (ezrin, radixin, moesin) family of proteins plays a central role in linking the cellular membranes to the cortical actin cytoskeleton. Merlin regulates contact inhibition and is an integral part of cell–cell junctions, while ERM proteins, ezrin, radixin and moesin, assist in the formation and maintenance of specialized plasma membrane structures and membrane vesicle structures. These two protein families share a common evolutionary history, having arisen and separated via gene duplication near the origin of metazoa. During approximately 0.5 billion years of evolution, the merlin and ERM family proteins have maintained both sequence and structural conservation to an extraordinary level. Comparing crystal structures of merlin-ERM proteins and their complexes, a picture emerges of the merlin-ERM proteins acting as switchable interaction hubs, assembling protein complexes on cellular membranes and linking them to the actin cytoskeleton. Given the high level of structural conservation between the merlin and ERM family proteins we speculate that they may function together.

Vascular-endothelial-cadherin modulates endothelial monolayer permeability

1999 ◽  
Vol 112 (12) ◽  
pp. 1915-1923 ◽  
Author(s):  
P.L. Hordijk ◽  
E. Anthony ◽  
F.P. Mul ◽  
R. Rientsma ◽  
L.C. Oomen ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Actin Cytoskeleton ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Transendothelial Migration ◽  
Stress Fibers ◽  
Vascular Endothelial ◽  
Monolayer Permeability ◽  
Actin Stress Fibers ◽  
Cell Cell

Vascular endothelial (VE)-cadherin is the endothelium-specific member of the cadherin family of homotypic cell adhesion molecules. VE-cadherin, but not the cell adhesion molecule platelet/endothelial cell adhesion molecule (PECAM-1), markedly colocalizes with actin stress fibers at cell-cell junctions between human umbilical vein endothelial cells. Inhibition of VE-cadherin-mediated, but not PECAM-1-mediated, adhesion induced reorganization of the actin cytoskeleton, loss of junctional VE-cadherin staining and loss of cell-cell adhesion. In functional assays, inhibition of VE-cadherin caused increased monolayer permeability and enhanced neutrophil transendothelial migration. In a complementary set of experiments, modulation of the actin cytoskeleton was found to strongly affect VE-cadherin distribution. Brief stimulation of the beta2-adrenergic receptor with isoproterenol induced a loss of actin stress fibers resulting in a linear, rather than ‘jagged’, VE-cadherin distribution. The concomitant, isoproterenol-induced, reduction in monolayer permeability was alleviated by a VE-cadherin-blocking antibody. Finally, cytoskeletal reorganization resulting from the inactivation of p21Rho caused a diffuse localization of VE-cadherin, which was accompanied by reduced cell-cell adhesion. Together, these data show that monolayer permeability and neutrophil transendothelial migration are modulated by VE-cadherin-mediated cell-cell adhesion, which is in turn controlled by the dynamics of the actin cytoskeleton.

Trimers of the fibronectin cell adhesion domain localize to actin filament bundles and undergo rearward translocation

2002 ◽  
Vol 115 (12) ◽  
pp. 2581-2590 ◽  
Author(s):  
Françoise Coussen ◽  
Daniel Choquet ◽  
Michael P. Sheetz ◽  
Harold P. Erickson
Keyword(s):  
Cell Adhesion ◽  
Fluorescence Microscopy ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Fiber Bundles ◽  
Cell Surfaces ◽  
Actin Fiber ◽  
Filament Bundles ◽  
Necessary And Sufficient ◽  
Small Clusters

Previous studies have shown that small beads coated with FN7-10, a four-domain cell adhesion fragment of fibronectin, bind to cell surfaces and translocate rearward. Here we investigate whether soluble constructs containing two to five FN7-10 units might be sufficient for activity. We have produced a monomer, three forms of dimers, a trimer and a pentamer of FN7-10,on the end of spacer arms. These oligomers could bind small clusters of up to five integrins. Fluorescence microscopy showed that the trimer and pentamer bound strongly to the cell surface, and within 5 minutes were prominently localized to actin fiber bundles. Monomers and dimers showed only diffuse localization. Beads coated with a low concentration (probably one complex per bead) of trimer or pentamer showed prolonged binding and rearward translocation, presumably with the translocating actin cytskeleton. Beads containing monomer or dimer showed only brief binding and diffusive movements. We conclude that clusters of three integrin-binding ligands are necessary and sufficient for coupling to and translocating with the actin cytoskeleton.

Evidence for a molecular complex consisting of Fyb/SLAP, SLP-76, Nck, VASP and WASP that links the actin cytoskeleton to Fcγ receptor signalling during phagocytosis

2001 ◽  
Vol 114 (23) ◽  
pp. 4307-4318
Author(s):  
Marc G. Coppolino ◽  
Matthias Krause ◽  
Petra Hagendorff ◽  
David A. Monner ◽  
William Trimble ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Molecular Complex ◽  
Actin Filaments ◽  
Sh2 Domain ◽  
Fcγ Receptors ◽  
Receptor Signalling ◽  
Src Homology 2 ◽  
Src Homology ◽  
Particle Ingestion ◽  
Syndrome Protein

Phagocytosis by macrophages and neutrophils involves the spatial and temporal reorganisation of the actin-based cytoskeleton at sites of particle ingestion. Local polymerisation of actin filaments supports the protrusion of pseudopodia that eventually engulf the particle. Here we have investigated in detail the cytoskeletal events initiated upon engagement of Fc receptors in macrophages. Ena/vasodilator-stimulated phosphoprotein (VASP) proteins were recruited to phagosomes forming around opsonised particles in both primary and immortalised macrophages. Not only did the localisation of Ena/VASP proteins coincide, spatially and temporally, with the phagocytosis-induced reorganisation of actin filaments, but their recruitment to the phagocytic cup was required for the remodelling of the actin cytoskeleton, extension of pseudopodia and efficient particle internalisation. We also report that SLP-76, Vav and profilin were recruited to forming phagosomes. Upon induction of phagocytosis, a large molecular complex, consisting in part of Ena/VASP proteins, the Fyn-binding/SLP-76-associated protein (Fyb/SLAP), Src-homology-2 (SH2)-domain-containing leukocyte protein of 76 kDa (SLP-76), Nck, and the Wiskott-Aldrich syndrome protein (WASP), was formed. Our findings suggest that activation of Fcγ receptors triggers two signalling events during phagocytosis: one through Fyb/SLAP that leads to recruitment of VASP and profilin; and another through Nck that promotes the recruitment of WASP. These converge to regulate actin polymerisation, controlling the assembly of actin structures that are essential for the process of phagocytosis.

Increased Tyr phosphorylation of ZO-1 during modification of tight junctions between glomerular foot processes

1995 ◽  
Vol 268 (3) ◽  
pp. F514-F524 ◽  
Author(s):  
H. Kurihara ◽  
J. M. Anderson ◽  
M. G. Farquhar
Keyword(s):  
Tight Junction ◽  
Tyrosine Phosphorylation ◽  
Tight Junctions ◽  
Mesangial Cells ◽  
Basal Membrane ◽  
Cell Junctions ◽  
Phosphorylated Proteins ◽  
Cell Matrix ◽  
Rapid Changes ◽  
And Control

The slit diaphragms between the glomerular epithelial foot processes represent a variant of the tight junction that are rapidly replaced by typical tight junctions after perfusion with protamine sulfate (PS). To investigate the mechanism of signaling involved, tyrosine phosphorylation of glomerular proteins was analyzed in newborn, PS-treated, and control rats using antiphosphotyrosine immunoglobulin G. In glomeruli of normal adults, phosphotyrosine (Ptyr) staining was confined largely to mesangial cells by immunofluorescence, whereas in newborn and PS-treated rats, the Ptyr signal was dramatically increased in the glomerular epithelium. By immunogold labeling, it was found that newly phosphorylated proteins were concentrated along the newly formed tight junctions (cell-cell junctions) and the basal membrane of the foot processes (cell-matrix junctions). By immunoblotting, several prominent bands were detected with anti-Ptyr in glomerular lysates of controls; in PS-treated rats, additional bands were detected at 225, 180, and 100 kDa. The 225-kDa protein was identified as ZO-1 by immunoprecipitation with anti-ZO-1 followed by immunoblotting with anti-Ptyr. These findings indicate that ZO-1 is one of the targets for tyrosine phosphorylation after PS treatment. They indicate that phosphorylation of tight junction and other proteins occurs during the formation of tight junctions in glomeruli under circumstances where there are rapid changes in epithelial cell shape.

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