scholarly journals Activation of RhoA by Lysophosphatidic Acid and Gα12/13 Subunits in Neuronal Cells: Induction of Neurite Retraction

1999 ◽  
Vol 10 (6) ◽  
pp. 1851-1857 ◽  
Author(s):  
Onno Kranenburg ◽  
Mieke Poland ◽  
Francis P. G. van Horck ◽  
David Drechsel ◽  
Alan Hall ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
G Protein ◽  
Lysophosphatidic Acid ◽  
Growth Cone ◽  
Kinase Inhibitors ◽  
Specific Binding ◽  
Neuronal Cells ◽  
Growth Cone Collapse ◽  
Neurite Retraction ◽  
Activation Assay

Neuronal cells undergo rapid growth cone collapse, neurite retraction, and cell rounding in response to certain G protein–coupled receptor agonists such as lysophosphatidic acid (LPA). These shape changes are driven by Rho-mediated contraction of the actomyosin-based cytoskeleton. To date, however, detection of Rho activation has been hampered by the lack of a suitable assay. Furthermore, the nature of the G protein(s) mediating LPA-induced neurite retraction remains unknown. We have developed a Rho activation assay that is based on the specific binding of active RhoA to its downstream effector Rho-kinase (ROK). A fusion protein of GST and the Rho-binding domain of ROK pulls down activated but not inactive RhoA from cell lysates. Using GST-ROK, we show that in N1E-115 neuronal cells LPA activates endogenous RhoA within 30 s, concomitant with growth cone collapse. Maximal activation occurs after 3 min when neurite retraction is complete and the actin cytoskeleton is fully contracted. LPA-induced RhoA activation is completely inhibited by tyrosine kinase inhibitors (tyrphostin 47 and genistein). Activated Gα12 and Gα13 subunits mimic LPA both in activating RhoA and in inducing RhoA-mediated cytoskeletal contraction, thereby preventing neurite outgrowth. We conclude that in neuronal cells, LPA activates RhoA to induce growth cone collapse and neurite retraction through a G12/13-initiated pathway that involves protein-tyrosine kinase activity.

scholarly journals Transmission of growth cone traction force through apCAM–cytoskeletal linkages is regulated by Src family tyrosine kinase activity

2001 ◽  
Vol 155 (3) ◽  
pp. 427-438 ◽  
Author(s):  
Daniel M. Suter ◽  
Paul Forscher
Keyword(s):  
Tyrosine Kinase ◽  
Growth Cone ◽  
Kinase Activity ◽  
Kinase Inhibitors ◽  
Traction Force ◽  
Tyrosine Kinase Activity ◽  
Cellular Mechanisms ◽  
Traction Forces ◽  
Kinase Activation ◽  
Neuronal Growth Cone

Tyrosine kinase activity is known to be important in neuronal growth cone guidance. However, underlying cellular mechanisms are largely unclear. Here, we report how Src family tyrosine kinase activity controls apCAM-mediated growth cone steering by regulating the transmission of traction forces through receptor–cytoskeletal linkages. Increased levels of tyrosine phosphorylation were detected at sites where beads coated with apCAM ligands were physically restrained to induce growth cone steering, but not at unrestrained bead binding sites. Interestingly, the rate and level of phosphotyrosine buildup near restrained beads were decreased by the myosin inhibitor 2,3-butanedione-2-monoxime, suggesting that tension promotes tyrosine kinase activation. While not affecting retrograde F-actin flow rates, genistein and the Src family selective tyrosine kinase inhibitors PP1 and PP2 strongly reduced the growth cone's ability to apply traction forces through apCAM–cytoskeletal linkages, assessed using the restrained bead interaction assay. Furthermore, increased levels of an activated Src family kinase were detected at restrained bead sites during growth cone steering events. Our results suggest a mechanism by which growth cones select pathways by sampling both the molecular nature of the substrate and its ability to withstand the application of traction forces.

scholarly journals Evidence that calcium may control neurite outgrowth by regulating the stability of actin filaments.

1989 ◽  
Vol 109 (3) ◽  
pp. 1229-1243 ◽  
Author(s):  
K L Lankford ◽  
P C Letourneau
Keyword(s):  
Neurite Outgrowth ◽  
Growth Cone ◽  
Actin Filaments ◽  
Monovalent Cation ◽  
Stabilizing Agent ◽  
Growth Cone Collapse ◽  
Neurite Retraction ◽  
Calcium Removal ◽  
The Stability ◽  
Triton X

We investigated the effects of calcium removal and calcium ionophores on the behavior and ultrastructure of cultured chick dorsal root ganglia (DRG) neurons to identify possible mechanisms by which calcium might regulate neurite outgrowth. Both calcium removal and the addition of calcium ionophores A23187 or ionomycin blocked outgrowth in previously elongating neurites, although in the case of calcium ionophores, changes in growth cone shape and retraction of neurites were also observed. Treatment with calcium ionophores significantly increased growth cone calcium. The ability of the microtubule stabilizing agent taxol to block A23187-induced neurite retraction and the ability of the actin stabilizing agent phalloidin to reverse both A23187-induced growth cone collapse and neurite retraction suggested that calcium acted on the cytoskeleton. Whole mount electron micrographs revealed an apparent disruption of actin filaments in the periphery (but not filopodia) of growth cones that were exposed to calcium ionophores in medium with normal calcium concentrations. This effect was not seen in cells treated with calcium ionophores in calcium-free medium or cells treated with the monovalent cation ionophore monensin, indicating that these effects were calcium specific. Ultrastructure of Triton X-100 extracted whole mounts further indicated that both microtubules and microfilaments may be more stable or extraction resistant after treatments which lower intracellular calcium. Taken together, the data suggest that calcium may control neurite elongation at least in part by regulating actin filament stability, and support a model for neurite outgrowth involving a balance between assembly and disassembly of the cytoskeleton.

scholarly journals Plexin-B1/RhoGEF–mediated RhoA activation involves the receptor tyrosine kinase ErbB-2

2004 ◽  
Vol 165 (6) ◽  
pp. 869-880 ◽  
Author(s):  
Jakub M. Swiercz ◽  
Rohini Kuner ◽  
Stefan Offermanns
Keyword(s):  
Tyrosine Kinase ◽  
Growth Cone ◽  
Receptor Tyrosine Kinase ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Axonal Growth ◽  
Dominant Negative ◽  
Growth Cone Collapse ◽  
Rhoa Activation ◽  
Axonal Growth Cone

Plexins are widely expressed transmembrane proteins that mediate the effects of semaphorins. The molecular mechanisms of plexin-mediated signal transduction are still rather unclear. Plexin-B1 has recently been shown to mediate activation of RhoA through a stable interaction with the Rho guanine nucleotide exchange factors PDZ-RhoGEF and LARG. However, it is unclear how the activity of plexin-B1 and its downstream effectors is regulated by its ligand Sema4D. Here, we show that plexin-B family members stably associate with the receptor tyrosine kinase ErbB-2. Binding of Sema4D to plexin-B1 stimulates the intrinsic tyrosine kinase activity of ErbB-2, resulting in the phosphorylation of both plexin-B1 and ErbB-2. A dominant-negative form of ErbB-2 blocks Sema4D-induced RhoA activation as well as axonal growth cone collapse in primary hippocampal neurons. Our data indicate that ErbB-2 is an important component of the plexin-B receptor system and that ErbB-2–mediated phosphorylation of plexin-B1 is critically involved in Sema4D-induced RhoA activation, which underlies cellular phenomena downstream of plexin-B1, including axonal growth cone collapse.

scholarly journals Nogo-A Beyond the RhoA/ROCK Pathway – Novel Components of Intracellular Nogo-A Signaling Cascades

2020 ◽  
Author(s):  
Martina A. Maibach ◽  
Ester Piovesana ◽  
Julia Kaiser ◽  
Mea M. Holm ◽  
Zorica Risic ◽  
...  
Keyword(s):  
Neurite Outgrowth ◽  
Growth Cone ◽  
Signaling Cascades ◽  
Growth Cone Collapse ◽  
Neurite Retraction ◽  
Downstream Effector ◽  
Fibre Growth ◽  
Growth Promoting

AbstractNogo-A is a well-characterized myelin-associated membrane protein that restricts fibre growth and the regenerative capacity of the adult central nervous system after injury. To date Nogo-A post-receptor signalling pathway research focused on the RhoA/ROCK cascade, which can lead to growth cone collapse and neurite retraction. Much less is known about continued intracellular Nogo-A signalling mediating long-term neurite outgrowth inhibition resulting from transcriptional and translational changes. Here, we propose a simple but highly reproducible in vitro assay to study Nogo-A related signaling and neurite outgrowth inhibition in general. Furthermore, we identified ERK1/2 as downstream effector of Nogo-A, partially mediating its neurite outgrowth inhibition. We describe ERK1/2 dependent changes of translational events such as elevation of RhoA levels within the growth cone, which may potentiate the cells’ responses to Nogo-A. We also observed Nogo-A dependent upregulation of the JAK/STAT pathway inhibitors SOCS3 and KLF4 and downregulation of insulin mediated phosphorylation of AKT, indicating direct negative crosstalk between Nogo-A signalling and the growth promoting JAK/STAT and AKT/mTORC1 pathways.

scholarly journals Downregulation of the Ras–Mitogen-Activated Protein Kinase Pathway by the EphB2 Receptor Tyrosine Kinase Is Required for Ephrin-Induced Neurite Retraction

2001 ◽  
Vol 21 (21) ◽  
pp. 7429-7441 ◽  
Author(s):  
Sabine Elowe ◽  
Sacha J. Holland ◽  
Sarang Kulkarni ◽  
Tony Pawson
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Mapk Pathway ◽  
Neuronal Cells ◽  
Mitogen Activated Protein Kinase ◽  
Neurite Retraction ◽  
Mitogen Activated Protein ◽  
Stimulation Of

ABSTRACT Activation of the EphB2 receptor tyrosine kinase by clustered ephrin-B1 induces growth cone collapse and neurite retraction in differentiated NG108 neuronal cells. We have investigated the cytoplasmic signaling events associated with EphB2-induced cytoskeletal reorganization in these neuronal cells. We find that unlike other receptor tyrosine kinases, EphB2 induces a pronounced downregulation of GTP-bound Ras and consequently of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway. A similar inhibition of the Ras-MAPK pathway was observed on stimulation of endogenous EphB2 in COS-1 cells. Inactivation of Ras, induced by ephrin B1 stimulation of NG108 neuronal cells, requires EphB2 tyrosine kinase activity and is blocked by a truncated form of p120-Ras GTPase-activating protein (p120-RasGAP), suggesting that EphB2 signals through the SH2 domain protein p120-RasGAP to inhibit the Ras-MAPK pathway. Suppression of Ras activity appears functionally important, since expression of a constitutively active variant of Ras impaired the ability of EphB2 to induce neurite retraction. In addition, EphB2 attenuated the elevation in ERK activation induced by attachment of NG108 cells to fibronectin, indicating that the EphB2 receptor can modulate integrin signaling to the Ras GTPase. These results suggest that a primary function of EphB2, a member of the most populous family of receptor tyrosine kinases, is to inactivate the Ras-MAPK pathway in a fashion that contributes to cytoskeletal reorganization and adhesion responses in neuronal growth cones.

scholarly journals Targeting anaplastic lymphoma kinase (ALK) gene alterations in neuroblastoma by using alkylating pyrrole-imidazole polyamides

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257718
Author(s):  
Yoko Ota ◽  
Hiroyuki Yoda ◽  
Takahiro Inoue ◽  
Takayoshi Watanabe ◽  
Yoshinao Shinozaki ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Anaplastic Lymphoma Kinase ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Specific Binding ◽  
Binding Motif ◽  
Human Neuroblastoma ◽  
Anaplastic Lymphoma ◽  
Alk Inhibitor ◽  
Inhibitor Resistance

Anaplastic lymphoma kinase (ALK) aberration is related to high-risk neuroblastomas and is an important therapeutic target. As acquired resistance to ALK tyrosine kinase inhibitors is inevitable, novel anti-ALK drug development is necessary in order to overcome potential drug resistance against ATP-competitive kinase inhibitors. In this study, to overcome ALK inhibitor resistance, we examined the growth inhibition effects of newly developed ALK-targeting pyrrole-imidazole polyamide CCC-003, which was designed to directly bind and alkylate DNA within the F1174L-mutated ALK gene. CCC-003 suppressed cell proliferation in ALK-mutated neuroblastoma cells. The expression of total and phosphorylated ALK was downregulated by CCC-003 treatment but not by treatment with a mismatch polyamide without any binding motif within the ALK gene region. CCC-003 preferentially bound to the DNA sequence with the F1174L mutation and significantly suppressed tumor progression in a human neuroblastoma xenograft mouse model. Our data suggest that the specific binding of CCC-003 to mutated DNA within the ALK gene exerts its anti-tumor activity through a mode of action that is distinct from those of other ALK inhibitors. In summary, our current study provides evidence for the potential of pyrrole-imidazole polyamide ALK inhibitor CCC-003 for the treatment of neuroblastoma thus offering a possible solution to the problem of tyrosine kinase inhibitor resistance.

scholarly journals Possible involvement of tyrosine kinase in collapsin-1-induced growth cone collapse

1999 ◽  
Vol 79 ◽  
pp. 261
Author(s):  
Yukio Sasaki ◽  
Megumi Noda ◽  
Yoshio Goshima ◽  
Motoyuki Shimonaka ◽  
Yoshimi Misu
Keyword(s):  
Tyrosine Kinase ◽  
Growth Cone ◽  
Growth Cone Collapse
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