Growth cones contain myosin II bipolar filament arrays

2002 ◽  
Vol 52 (2) ◽  
pp. 91-96 ◽  
Author(s):  
Paul C. Bridgman
Keyword(s):  
Myosin Ii ◽  
Growth Cones ◽  
Bipolar Filament

Localization of myosin II A and B isoforms in cultured neurons

1995 ◽  
Vol 108 (12) ◽  
pp. 3661-3670 ◽  
Author(s):  
M.W. Rochlin ◽  
K. Itoh ◽  
R.S. Adelstein ◽  
P.C. Bridgman
Keyword(s):  
Myosin Heavy Chain ◽  
Growth Cone ◽  
Heavy Chain ◽  
Marginal Zone ◽  
Myosin Ii ◽  
Growth Cones ◽  
Filamentous Actin ◽  
Differential Interference Contrast Microscopy ◽  
Actin Bundles ◽  
Ganglion Neurons

Tension generated by growth cones regulates both the rate and the direction of neurite growth. The most likely effectors of tension generation are actin and myosins. We are investigating the role of conventional myosin in growth cone advance. In this paper we report the localization of the two most prominent isoforms of brain myosin II in growth cones, neurites and cell bodies of rat superior cervical ganglion neurons. Affinity purified polyclonal antibodies were prepared against unique peptide sequences from human and rat A and B isoforms of myosin heavy chain. Although each of these antibodies brightly stained nonneuronal cells, antibodies to myosin heavy chain B stained neurons with greater intensity than antibodies to myosin heavy chain A. In growth cones, myosin heavy chain B was most concentrated in the margin bordering the thickened, organelle-rich central region and the thin, actin-rich peripheral region. The staining colocalized with actin bundles proximal and distal to the marginal zone, though the staining was more prominent proximally. The trailing edge of growth cones and the distal portion of the neurite often had a rimmed appearance, but more proximal regions of neurites had cytoplasmic labelling. Localizing MHC-B in growth cones previously monitored during advance (using differential interference contrast microscopy) revealed a positive correlation with edges at which retraction had just occurred and a negative correlation with lamellipodia that had recently undergone protrusion. Cell bodies were brightly labelled for myosin heavy chain B. Myosin heavy chain A staining was dimmer and its colocalization with filamentous actin bundles in growth cones was less striking than that of myosin heavy chain B. Growth cones stained for both myosin heavy chain A and B revealed that the two antigens overlapped frequently, but not exclusively, and that myosin heavy chain A lacked the elevation in the marginal zone that was characteristic of myosin heavy chain B. The pattern of staining we observed is consistent with a prominent role for myosin heavy chain B in either generating tension between widely separated areas of the growth cone, or bundling of actin filaments, which would enable other motors to effect this tension. These data support the notion that conventional myosin is important in growth cone advance and turning.

scholarly journals Lamin A/C deficiency enables increased myosin-II bipolar filament ensembles that promote divergent actomyosin network anomalies through self-organization

2020 ◽  
Vol 31 (21) ◽  
pp. 2363-2378
Author(s):  
O’Neil Wiggan ◽  
Jennifer G. DeLuca ◽  
Timothy J. Stasevich ◽  
James R. Bamburg
Keyword(s):  
Myosin Ii ◽  
Nuclear Lamina ◽  
Self Organization ◽  
Lamin A ◽  
Filament Assembly ◽  
Bipolar Filament ◽  
Network Anomalies

This study identifies that disruption of the nuclear lamina via lamin A/C depletion results in contrasting actomyosin cytoskeletal patterning, linked to increased myosin-II filament assembly.

scholarly journals Role of Myosin II in Motility and in Force Generation of DRG Growth Cones

2013 ◽  
Vol 104 (2) ◽  
pp. 477a
Author(s):  
Ladan Amin ◽  
Wasim Amin Sayyad ◽  
Erika Ercolini ◽  
Jelena Ban ◽  
Hiba Sheheitli ◽  
...  
Keyword(s):  
Myosin Ii ◽  
Growth Cones ◽  
Force Generation

scholarly journals Role of Myosin II in Axon Outgrowth

2003 ◽  
Vol 51 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Jacquelyn Brown ◽  
Paul C. Bridgman
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Myosin Ii ◽  
Traction Force ◽  
Growth Cones ◽  
Matrix Proteins ◽  
Retrograde Flow ◽  
Complex Interactions ◽  
Cell Adhesion Proteins

The initial stages of nerve outgrowth carried out by growth cones occur in three fundamental cyclic steps. Each of these steps appears to require myosin II activity to variable degrees. The steps include the following: (a) exploration, involving extensions and retractions that are driven and controlled by the interaction of actin retrograde flow and polymerization; (b) adhesion of new extensions to the substrate, which has been shown to be mediated by complex interactions between extracellular matrix proteins, cell adhesion proteins, and the actin cytoskeleton; and (c) traction force generated during forward advance of the growth cone, resulting in the production of tension on the neurite.

scholarly journals Lamin A/C Deficiency Enables Increased Myosin2 Bipolar Filament Ensembles Which Promote Divergent Actomyosin Network Anomalies Through Self Organization

2020 ◽  
Author(s):  
O’Neil Wiggan ◽  
Jennifer G. DeLuca ◽  
Timothy J. Stasevich ◽  
James R. Bamburg
Keyword(s):  
Live Cell Imaging ◽  
Serum Response Factor ◽  
Myosin Ii ◽  
Lamin A ◽  
Fiber Assembly ◽  
Cytoplasmic Actomyosin ◽  
Bipolar Filament ◽  
Actin Comet Tails ◽  
Serum Response ◽  
Transcriptional Feedback

AbstractNuclear envelope proteins influence cell cytoarchitecure by poorly understood mechanisms. Here we show that siRNA-mediated silencing of lamin A/C (LMNA) promotes contrasting stress fiber assembly and disassembly in individual cells and within cell populations. We show that LMNA deficient cells have elevated myosin-II bipolar filament accumulations, irregular formation of actin comet tails and podosome-like adhesions, increased steady state nuclear localization of the mechanosensitive transcription factors MKL1 and YAP, and induced expression of some MKL1/Serum Response Factor (SRF) regulated genes such as that encoding myosin-IIA (MYH9). Our studies utilizing live cell imaging and pharmacological inhibition of myosin-II, support a mechanism of deregulated myosin-II self-organizing activity at the nexus of divergent actin cytoskeletal aberrations resultant from LMNA loss. In light of our results, we propose a model of how the nucleus, via linkage to the cytoplasmic actomyosin network, may act to control myosin-II contractile behavior through both mechanical and transcriptional feedback mechanisms.

scholarly journals Protein kinase C activation decreases peripheral actin network density and increases central nonmuscle myosin II contractility in neuronal growth cones

2013 ◽  
Vol 24 (19) ◽  
pp. 3097-3114 ◽  
Author(s):  
Qing Yang ◽  
Xiao-Feng Zhang ◽  
David Van Goor ◽  
Ashleigh P. Dunn ◽  
Callen Hyland ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Myosin Ii ◽  
Growth Cones ◽  
Network Density ◽  
Actin Network ◽  
Neuronal Growth ◽  
Kinase C ◽  
Neuronal Growth Cones ◽  
Pkc Activation

Protein kinase C (PKC) can dramatically alter cell structure and motility via effects on actin filament networks. In neurons, PKC activation has been implicated in repulsive guidance responses and inhibition of axon regeneration; however, the cytoskeletal mechanisms underlying these effects are not well understood. Here we investigate the acute effects of PKC activation on actin network structure and dynamics in large Aplysia neuronal growth cones. We provide evidence of a novel two-tiered mechanism of PKC action: 1) PKC activity enhances myosin II regulatory light chain phosphorylation and C-kinase–potentiated protein phosphatase inhibitor phosphorylation. These effects are correlated with increased contractility in the central cytoplasmic domain. 2) PKC activation results in significant reduction of P-domain actin network density accompanied by Arp2/3 complex delocalization from the leading edge and increased rates of retrograde actin network flow. Our results show that PKC activation strongly affects both actin polymerization and myosin II contractility. This synergistic mode of action is relevant to understanding the pleiotropic reported effects of PKC on neuronal growth and regeneration.

Myosin II functions in actin-bundle turnover in neuronal growth cones

2006 ◽  
Vol 8 (3) ◽  
pp. 216-226 ◽  
Author(s):  
Nelson A. Medeiros ◽  
Dylan T. Burnette ◽  
Paul Forscher
Keyword(s):  
Myosin Ii ◽  
Growth Cones ◽  
Neuronal Growth ◽  
Actin Bundle ◽  
Neuronal Growth Cones

scholarly journals Myosin 1c and myosin IIB serve opposing roles in lamellipodial dynamics of the neuronal growth cone

2002 ◽  
Vol 158 (7) ◽  
pp. 1207-1217 ◽  
Author(s):  
Thomas J. Diefenbach ◽  
Vaughan M. Latham ◽  
Dean Yimlamai ◽  
Canwen A. Liu ◽  
Ira M. Herman ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Neurite Outgrowth ◽  
Growth Cone ◽  
Dorsal Root ◽  
Myosin Ii ◽  
Growth Cones ◽  
Neuronal Growth ◽  
Rapid Reduction ◽  
Neuronal Growth Cone

The myosin family of motor proteins is implicated in mediating actin-based growth cone motility, but the roles of many myosins remain unclear. We previously implicated myosin 1c (M1c; formerly myosin Iβ) in the retention of lamellipodia (Wang et al., 1996). Here we address the role of myosin II (MII) in chick dorsal root ganglion neuronal growth cone motility and the contribution of M1c and MII to retrograde F-actin flow using chromophore-assisted laser inactivation (CALI). CALI of MII reduced neurite outgrowth and growth cone area by 25%, suggesting a role for MII in lamellipodial expansion. Micro-CALI of MII caused a rapid reduction in local lamellipodial protrusion in growth cones with no effects on filopodial dynamics. This is opposite to micro-CALI of M1c, which caused an increase in lamellipodial protrusion. We used fiduciary beads (Forscher et al., 1992) to observe retrograde F-actin flow during the acute loss of M1c or MII. Micro-CALI of M1c reduced retrograde bead flow by 76%, whereas micro-CALI of MII or the MIIB isoform did not. Thus, M1c and MIIB serve opposite and nonredundant roles in regulating lamellipodial dynamics, and M1c activity is specifically required for retrograde F-actin flow.

scholarly journals Emerging roles for myosin II and cytoplasmic dynein in migrating neurons and growth cones

2009 ◽  
Vol 19 (7) ◽  
pp. 347-355 ◽  
Author(s):  
Richard B. Vallee ◽  
Garrett E. Seale ◽  
Jin-Wu Tsai
Keyword(s):  
Myosin Ii ◽  
Growth Cones ◽  
Cytoplasmic Dynein

Magnesium Chloride is an Effective Therapeutic Agent for Prostate Cancer

2018 ◽  
Vol 8 (1) ◽  
pp. 62 ◽  
Author(s):  
Julianna Maria Santos ◽  
Fazle Hussain
Keyword(s):  
Prostate Cancer ◽  
Magnesium Chloride ◽  
Epithelial Mesenchymal Transition ◽  
Chromatin Condensation ◽  
Myosin Ii ◽  
In Vivo Studies ◽  
Migration Speed ◽  
Mesenchymal Transition

Background: Reduced levels of magnesium can cause several diseases and increase cancer risk. Motivated by magnesium chloride’s (MgCl2) non-toxicity, physiological importance, and beneficial clinical applications, we studied its action mechanism and possible mechanical, molecular, and physiological effects in prostate cancer with different metastatic potentials.Methods: We examined the effects of MgCl2, after 24 and 48 hours, on apoptosis, cell migration, expression of epithelial mesenchymal transition (EMT) markers, and V-H+-ATPase, myosin II (NMII) and the transcription factor NF Kappa B (NFkB) expressions.Results: MgCl2 induces apoptosis, and significantly decreases migration speed in cancer cells with different metastatic potentials.  MgCl2 reduces the expression of V-H+-ATPase and myosin II that facilitates invasion and metastasis, suppresses the expression of vimentin and increases expression of E-cadherin, suggesting a role of MgCl2 in reversing the EMT. MgCl2 also significantly increases the chromatin condensation and decreases NFkB expression.Conclusions: These results suggest a promising preventive and therapeutic role of MgCl2 for prostate cancer. Further studies should explore extending MgCl2 therapy to in vivo studies and other cancer types.Keywords: Magnesium chloride, prostate cancer, migration speed, V-H+-ATPase, and EMT.

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