Editorial: Cytoskeleton Dynamics as Master Regulator of Organelle Reorganization and Intracellular Signaling for Cell-Cell Competition

Pulmonary endothelium forms a semiselective barrier that regulates fluid balance and leukocyte trafficking. During the course of lung inflammation, neurohumoral mediators and oxidants act on endothelial cells to induce intercellular gaps permissive for transudation of proteinaceous fluid from blood into the interstitium. Intracellular signals activated by neurohumoral mediators and oxidants that evoke intercellular gap formation are incompletely understood. Cytosolic Ca2+ concentration ([Ca2+]i) and cAMP are two signals that importantly dictate cell-cell apposition. Although increased [Ca2+]ipromotes disruption of the macrovascular endothelial cell barrier, increased cAMP enhances endothelial barrier function. Furthermore, during the course of inflammation, elevated endothelial cell [Ca2+]idecreases cAMP to facilitate intercellular gap formation. Given the significance of both [Ca2+]iand cAMP in mediating cell-cell apposition, this review addresses potential sites of cross talk between these two intracellular signaling pathways. Emerging data also indicate that endothelial cells derived from different vascular sites within the pulmonary circulation exhibit distinct sensitivities to permeability-inducing stimuli; that is, elevated [Ca2+]ipromotes macrovascular but not microvascular barrier disruption. Thus this review also considers the roles of [Ca2+]iand cAMP in mediating site-specific alterations in endothelial permeability.

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Ephrin-B3 controls excitatory synapse density through cell-cell competition for EphBs

eLife ◽

10.7554/elife.41563 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 3

Author(s):

Nathan T Henderson ◽

Sylvain J Le Marchand ◽

Martin Hruska ◽

Simon Hippenmeyer ◽

Liqun Luo ◽

...

Keyword(s):

Cortical Neurons ◽

Spine Density ◽

Cell Competition ◽

Intrinsic Factors ◽

Genetic Mouse Model ◽

Synapse Density ◽

A Cell ◽

Cell Cell

Cortical networks are characterized by sparse connectivity, with synapses found at only a subset of axo-dendritic contacts. Yet within these networks, neurons can exhibit high connection probabilities, suggesting that cell-intrinsic factors, not proximity, determine connectivity. Here, we identify ephrin-B3 (eB3) as a factor that determines synapse density by mediating a cell-cell competition that requires ephrin-B-EphB signaling. In a microisland culture system designed to isolate cell-cell competition, we find that eB3 determines winning and losing neurons in a contest for synapses. In a Mosaic Analysis with Double Markers (MADM) genetic mouse model system in vivo the relative levels of eB3 control spine density in layer 5 and 6 neurons. MADM cortical neurons in vitro reveal that eB3 controls synapse density independently of action potential-driven activity. Our findings illustrate a new class of competitive mechanism mediated by trans-synaptic organizing proteins which control the number of synapses neurons receive relative to neighboring neurons.

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Control of cortical cytoskeleton-membrane interaction by RhoA regulates peripheral nerve myelination

10.1101/2021.11.09.467948 ◽

2021 ◽

Author(s):

Ana I. Seixas ◽

Miguel R. G. Morais ◽

Cord Brakebusch ◽

Jo&atildeo B. Relvas

Keyword(s):

Schwann Cell ◽

Schwann Cells ◽

Rho Gtpases ◽

Intracellular Signaling ◽

Cell Interaction ◽

Actin Dynamics ◽

Specific Gene ◽

Cortical Actin ◽

Membrane Attachment ◽

Cytoskeleton Dynamics

Bidirectional transmission of mechanical and biochemical signals is integral to cell-environment communication and underlies the function of Schwann cells, the myelinating glia of the peripheral nervous system. As major integrators of "outside-in" signaling, Rho GTPases link actin cytoskeleton dynamics with cellular architecture to regulate adhesion and cell deformation. Using Schwann cell-specific gene inactivation, we discovered that RhoA promotes the initiation of myelination, axonal wrapping and axial spreading of Schwann cells, and is later required to restrict myelin growth in peripheral nerves. These effects are mediated by modulation of actomyosin contractility, actin dynamics and cortical actin-membrane attachment, which collectively couple tensional forces to intracellular signaling that regulate axon-Schwann cell interaction and myelin synthesis. This work establishes RhoA as an intrinsic regulator of a biomechanical response that controls the switch of Schwann cells towards the myelinating and the homeostatic states.

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Lysophosphatidic acid and bFGF control different modes in proliferating myoblasts.

The Journal of Cell Biology ◽

10.1083/jcb.132.1.181 ◽

1996 ◽

Vol 132 (1) ◽

pp. 181-193 ◽

Cited By ~ 60

Author(s):

S Yoshida ◽

A Fujisawa-Sehara ◽

T Taki ◽

K Arai ◽

Y Nabeshima

Keyword(s):

Lysophosphatidic Acid ◽

Intracellular Signaling ◽

Myogenic Differentiation ◽

Mrna Level ◽

Biological Significance ◽

Cell Contact ◽

C2c12 Myoblast ◽

Bhlh Proteins ◽

Cell Cell

Myogenic cells provide excellent in vitro models for studying the cell growth and differentiation. In this study we report that lysophosphatidic acid (LPA), a bioactive phospholipid contained in serum, stimulates the growth and inhibits the differentiation of mouse C2C12 myoblast cells, in a distinct manner from basic fibroblast growth factor (bFGF) whose mitotic and anti-differentiation actions have been well investigated. These actions of LPA were both blocked by pertussis toxin, suggesting the involvement of Gi class of G proteins, whereas bFGF acts through receptor tyrosine kinases. Detailed analysis revealed that LPA and bFGF act differently in regulating the myogenic basic helix-loop-helix (bHLH) proteins, the key players in myogenic differentiation process. LPA stimulates the proliferation of undifferentiated myoblasts allowing the continued expression of MyoD, but in contrast, bFGF does so with the MyoD expression suppressed at the mRNA level. Both compounds maintain the myf-5 expression, and suppress the myogenin expression. In addition, while LPA did not inhibit cell-cell contact-induced differentiation, bFGF strongly inhibited this process. Furthermore, LPA and bFGF act cooperatively in their mitogenic and anti-differentiation abilities. These findings indicate that LPA and bFGF differently stimulate intracellular signaling pathways, resulting in proliferating myoblasts each bearing a distinct expression pattern of myogenic bHLH proteins and distinct differentiation potentials in response to cell-cell contact, and illustrate the biological significance of Gi-mediated and tyrosine kinase-mediated signals.

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The GPI-anchored adhesion molecule F3 induces tyrosine phosphorylation: involvement of the FNIII repeats

Journal of Cell Science ◽

10.1242/jcs.109.3.699 ◽

1996 ◽

Vol 109 (3) ◽

pp. 699-704 ◽

Cited By ~ 1

Author(s):

M. Cervello ◽

V. Matranga ◽

P. Durbec ◽

G. Rougon ◽

S. Gomez

Keyword(s):

Tyrosine Kinase ◽

Tyrosine Phosphorylation ◽

Cho Cells ◽

Intracellular Signaling ◽

Protein Tyrosine Kinase ◽

Cross Linking ◽

Protein Tyrosine ◽

Intracellular Signaling Pathway ◽

Type Iii ◽

Cell Cell

The glycosyl-phosphatidylinositol (GPI)-anchored F3 molecule, a member of the Ig superfamily made up of Ig and FNIII-like domains, is involved in cell-cell adhesion, neuronal pathfinding and fasciculation. Little is known about the mechanism(s) that governs the F3-mediated cell-cell recognition. In particular, it is not known whether F3 transduces signals across the membrane. Here we show that in F3-transfected CHO cells (1A cells) an increase in tyrosine phosphorylation occurs during F3-mediated aggregation. Moreover, under aggregation conditions F3 immunoprecipitated from 32P-metabolically labeled 1A cells associated with three major phosphorylated proteins. Interestingly, genistein inhibited the F3-mediated aggregation. Increased tyrosine phosphorylation was also observed using antibody-mediated F3-cross-linking. Furthermore, F3 expressed both in 1A cells and in post-natal mouse cerebellum forms non-covalent soluble complexes with protein tyrosine kinase(s). In cerebellum the F3-associated kinase was identified as fyn. By contrast, a truncated F3 protein, expressed in CHO cells, from which all the FN type III repeats have been deleted, does not associate with a kinase. Cross-linking of the F3-truncated form does not induce modulation of tyrosine phosphorylation. Taken together these data demonstrate that F3 is a molecule that transduces signals through both association with protein tyrosine kinase and modulation of protein tyrosine phosphorylation. The presence of FN type III domains is essential for the activation of the intracellular signaling pathway.

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Armc8 is an evolutionarily conserved armadillo protein involved in cell–cell adhesion complexes through multiple molecular interactions

Bioscience Reports ◽

10.1042/bsr20180604 ◽

2019 ◽

Vol 39 (8) ◽

Cited By ~ 1

Author(s):

Ismail Sahin Gul ◽

Paco Hulpiau ◽

Ellen Sanders ◽

Frans van Roy ◽

Jolanda van Hengel

Keyword(s):

Intracellular Signaling ◽

Protein Structures ◽

Hybrid Approach ◽

Evolutionary Relationship ◽

Similar Process ◽

Cellular Functions ◽

Human Ortholog ◽

Armadillo Repeat ◽

Relationship Of ◽

Cell Cell

Abstract Armadillo-repeat-containing protein 8 (Armc8) belongs to the family of armadillo-repeat containing proteins, which have been found to be involved in diverse cellular functions including cell–cell contacts and intracellular signaling. By comparative analyses of armadillo repeat protein structures and genomes from various premetazoan and metazoan species, we identified orthologs of human Armc8 and analyzed in detail the evolutionary relationship of Armc8 genes and their encoded proteins. Armc8 is a highly ancestral armadillo protein although not present in yeast. Consequently, Armc8 is not the human ortholog of yeast Gid5/Vid28. Further, we performed a candidate approach to characterize new protein interactors of Armc8. Interactions between Armc8 and specific δ-catenins (plakophilins-1, -2, -3 and p0071) were observed by the yeast two-hybrid approach and confirmed by co-immunoprecipitation and co-localization. We also showed that Armc8 interacts specifically with αE-catenin but neither with αN-catenin nor with αT-catenin. Degradation of αE-catenin has been reported to be important in cancer and to be regulated by Armc8. A similar process may occur with respect to plakophilins in desmosomes. Deregulation of desmosomal proteins has been considered to contribute to tumorigenesis.

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Integration of cell cycle signals by multi-PAS domain kinases

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1808543115 ◽

2018 ◽

Vol 115 (30) ◽

pp. E7166-E7173 ◽

Cited By ~ 8

Author(s):

Thomas H. Mann ◽

Lucy Shapiro

Keyword(s):

Intracellular Signaling ◽

Spatial Information ◽

Caulobacter Crescentus ◽

Master Regulator ◽

Cellular Behavior ◽

Cell Pole ◽

Spatial Niche ◽

Spatiotemporal Control ◽

Stimulation Of

Spatial control of intracellular signaling relies on signaling proteins sensing their subcellular environment. In many cases, a large number of upstream signals are funneled to a master regulator of cellular behavior, but it remains unclear how individual proteins can rapidly integrate a complex array of signals within the appropriate spatial niche within the cell. As a model for how subcellular spatial information can control signaling activity, we have reconstituted the cell pole-specific control of the master regulator kinase/phosphatase CckA from the asymmetrically dividing bacterium Caulobacter crescentus. CckA is active as a kinase only when it accumulates within a microdomain at the new cell pole, where it colocalizes with the pseudokinase DivL. Both proteins contain multiple PAS domains, a multifunctional class of sensory domains present across the kingdoms of life. Here, we show that CckA uses its PAS domains to integrate information from DivL and its own oligomerization state to control the balance of its kinase and phosphatase activities. We reconstituted the DivL–CckA complex on liposomes in vitro and found that DivL directly controls the CckA kinase/phosphatase switch, and that stimulation of either CckA catalytic activity depends on the second of its two PAS domains. We further show that CckA oligomerizes through a multidomain interaction that is critical for stimulation of kinase activity by DivL, while DivL stimulation of CckA phosphatase activity is independent of CckA homooligomerization. Our results broadly demonstrate how signaling factors can leverage information from their subcellular niche to drive spatiotemporal control of cell signaling.

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Identification of Fer Tyrosine Kinase Localized on Microtubules as a Platelet Endothelial Cell Adhesion Molecule-1 Phosphorylating Kinase in Vascular Endothelial Cells

Molecular Biology of the Cell ◽

10.1091/mbc.e03-02-0080 ◽

2003 ◽

Vol 14 (9) ◽

pp. 3553-3564 ◽

Cited By ~ 48

Author(s):

Naoko Kogata ◽

Michitaka Masuda ◽

Yuji Kamioka ◽

Akiko Yamagishi ◽

Akira Endo ◽

...

Keyword(s):

Endothelial Cells ◽

Tyrosine Kinase ◽

Tyrosine Phosphorylation ◽

Adhesion Molecule ◽

Intracellular Signaling ◽

Vascular Endothelial Cells ◽

Expression Cloning ◽

Vascular Endothelial ◽

Cell Contacts ◽

Cell Cell

Platelet endothelial adhesion molecule-1 (PECAM-1) is a part of intercellular junctions and triggers intracellular signaling cascades upon homophilic binding. The intracellular domain of PECAM-1 is tyrosine phosphorylated upon homophilic engagement. However, it remains unclear which tyrosine kinase phosphorylates PECAM-1. We sought to isolate tyrosine kinases responsible for PECAM-1 phosphorylation and identified Fer as a candidate, based on expression cloning. Fer kinase specifically phosphorylated PECAM-1 at the immunoreceptor tyrosine-based inhibitory motif. Notably, Fer induced tyrosine phosphorylation of SHP-2, which is known to bind to the immunoreceptor tyrosine-based inhibitory motif of PECAM-1, and Fer also induced tyrosine phosphorylation of Gab1 (Grb2-associated binder-1). Engagement-dependent PECAM-1 phosphorylation was inhibited by the overexpression of a kinase-inactive mutant of Fer, suggesting that Fer is responsible for the tyrosine phosphorylation upon PECAM-1 engagement. Furthermore, by using green fluorescent protein-tagged Fer and a time-lapse fluorescent microscope, we found that Fer localized at microtubules in polarized and motile vascular endothelial cells. Fer was dynamically associated with growing microtubules in the direction of cell-cell contacts, where p120catenin, which is known to associate with Fer, colocalized with PECAM-1. These results suggest that Fer localized on microtubules may play an important role in phosphorylation of PECAM-1, possibly through its association with p120catenin at nascent cell-cell contacts.

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Integration of cell cycle signals by multi-PAS domain kinases

10.1101/323444 ◽

2018 ◽

Cited By ~ 1

Author(s):

Thomas H. Mann ◽

Lucy Shapiro

Keyword(s):

Intracellular Signaling ◽

Spatial Information ◽

Caulobacter Crescentus ◽

Subcellular Location ◽

Master Regulator ◽

Phosphatase Activities ◽

Cell Pole ◽

Sensor Proteins ◽

Stimulation Of

AbstractSpatial control of intracellular signaling relies on signaling proteins sensing their subcellular environment. In many cases, a large number of upstream signals are funneled to a master regulator of cellular behavior, but it remains unclear how individual proteins can rapidly integrate a complex array of signals within the appropriate spatial niche within the cell. As a model for how subcellular spatial information can control signaling activity, we have reconstituted the cell pole-specific control of the master regulator kinase/phosphatase CckA from the asymmetrically dividing bacterium Caulobacter crescentus. CckA is active as a kinase only when it accumulates within a microdomain at the new cell pole, where it co-localizes with the pseudokinase DivL. Both proteins contain multiple PAS domains, a multifunctional class of sensory domains present across the kingdoms of life. Here, we show that CckA uses its PAS domains to integrate information from DivL and on its own oligomerization state to control the balance of its kinase and phosphatase activities. We reconstituted the DivL-CckA complex on liposomes in vitro and found that DivL directly controls the CckA kinase-phosphatase switch, and that stimulation of either CckA catalytic activity depends on the second of its two PAS domains. We further show that CckA oligomerizes through a multi-domain interaction that is critical for stimulation of kinase activity by DivL, while DivL stimulation of CckA phosphatase activity is independent of CckA homo-oligomerization. Our results broadly demonstrate how signaling factors can leverage information from their subcellular niche to drive spatiotemporal control of cell signaling.SignificanceCells must constantly make decisions involving many pieces of information at a molecular level. Kinases containing multiple PAS sensory domains detect multiple signals to determine their signaling outputs. In the asymmetrically dividing bacterium Caulobacter crescentus, the multi-sensor proteins DivL and CckA promote different cell types depending upon their subcellular location. We reconstituted the DivL-CckA interaction in vitro and showed that specific PAS domains of each protein function to switch CckA between kinase and phosphatase activities, which reflects their functions in vivo. Within the context of the cell, our reconstitution illustrates how multi-sensor proteins can use their subcellular location to regulate their signaling functions.

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