scholarly journals Repulsive axon guidance cues ephrin-A2 and slit3 stop protrusion of the growth cone leading margin concurrently with inhibition of ADF/cofilin and ERM proteins

Cytoskeleton ◽  
2012 ◽  
Vol 69 (7) ◽  
pp. 496-505 ◽  
Author(s):  
Bonnie M. Marsick ◽  
Florence K. Roche ◽  
Paul C. Letourneau
Keyword(s):  
Axon Guidance ◽  
Growth Cone ◽  
Erm Proteins ◽  
Guidance Cues

scholarly journals A pair of E3 ubiquitin ligases compete to regulate filopodial dynamics and axon guidance

2019 ◽  
Vol 219 (1) ◽  
Author(s):  
Nicholas P. Boyer ◽  
Laura E. McCormick ◽  
Shalini Menon ◽  
Fabio L. Urbina ◽  
Stephanie L. Gupton
Keyword(s):  
Axon Guidance ◽  
Growth Cone ◽  
Ubiquitin Ligases ◽  
Critical Element ◽  
E3 Ubiquitin Ligases ◽  
Related Protein ◽  
Guidance Cues ◽  
Guidance Cue ◽  
Neuronal Connections ◽  
Novel Model

Appropriate axon guidance is necessary to form accurate neuronal connections. Axon guidance cues that stimulate cytoskeletal reorganization within the growth cone direct axon navigation. Filopodia at the growth cone periphery have long been considered sensors for axon guidance cues, yet how they respond to extracellular cues remains ill defined. Our previous work found that the filopodial actin polymerase VASP and consequently filopodial stability are negatively regulated via nondegradative TRIM9-dependent ubiquitination. Appropriate VASP ubiquitination and deubiquitination are required for axon turning in response to the guidance cue netrin-1. Here we show that the TRIM9-related protein TRIM67 outcompetes TRIM9 for interacting with VASP and antagonizes TRIM9-dependent VASP ubiquitination. The surprising antagonistic roles of two closely related E3 ubiquitin ligases are required for netrin-1–dependent filopodial responses, axon turning and branching, and fiber tract formation. We suggest a novel model in which coordinated regulation of VASP ubiquitination by a pair of interfering ligases is a critical element of VASP dynamics, filopodial stability, and axon guidance.

scholarly journals A pair of E3 ubiquitin ligases compete to regulate filopodial dynamics and axon guidance TRIM67 regulates filopodial stability and axon guidance

2019 ◽  
Author(s):  
Nicholas P. Boyer ◽  
Laura E. McCormick ◽  
Fabio L. Urbina ◽  
Stephanie L. Gupton
Keyword(s):  
Axon Guidance ◽  
Growth Cone ◽  
Ubiquitin Ligases ◽  
Critical Element ◽  
Related Protein ◽  
Fiber Tract ◽  
Guidance Cues ◽  
Guidance Cue ◽  
Neuronal Connections ◽  
Novel Model

ABSTRACTAppropriate axon guidance is necessary to form accurate neuronal connections. Guidance cues stimulate reorganization of the cytoskeleton within the distal growth cone at the tip of the extending axon. Filopodia at the periphery of the growth cone have long been considered sensors for axon guidance cues, yet how they perceive and respond to extracellular cues remains ill-defined. Our previous work found that the filopodial actin polymerase VASP is regulated via TRIM9-dependent nondegradative ubiquitination, and that appropriate VASP ubiquitination and deubiquitination are required for axon turning in response to the guidance cue netrin-1. Here we show that the TRIM9-related protein TRIM67 antagonizes VASP ubiquitination by outcompeting the TRIM9:VASP interaction. This antagonistic role is required for netrin-1 dependent filopodial responses, axon turning and branching, and fiber tract formation. We suggest a novel model that coordinated regulation of nondegradative VASP ubiquitination by a pair of ligases is a critical element of axon guidance.

Retinal axon growth cones respond to EphB extracellular domains as inhibitory axon guidance cues

Development ◽  
2001 ◽  
Vol 128 (15) ◽  
pp. 3041-3048 ◽  
Author(s):  
Eric Birgbauer ◽  
Stephen F. Oster ◽  
Christophe G. Severin ◽  
David W. Sretavan
Keyword(s):  
Axon Guidance ◽  
Optic Disc ◽  
Growth Cone ◽  
Axon Growth ◽  
Growth Cones ◽  
Axon Pathfinding ◽  
Guidance Cues ◽  
Extracellular Domains ◽  
Retinal Axons ◽  
Retinal Axon

Axon pathfinding relies on cellular signaling mediated by growth cone receptor proteins responding to ligands, or guidance cues, in the environment. Eph proteins are a family of receptor tyrosine kinases that govern axon pathway development, including retinal axon projections to CNS targets. Recent examination of EphB mutant mice, however, has shown that axon pathfinding within the retina to the optic disc is dependent on EphB receptors, but independent of their kinase activity. Here we show a function for EphB1, B2 and B3 receptor extracellular domains (ECDs) in inhibiting mouse retinal axons when presented either as substratum-bound proteins or as soluble proteins directly applied to growth cones via micropipettes. In substratum choice assays, retinal axons tended to avoid EphB-ECDs, while time-lapse microscopy showed that exposure to soluble EphB-ECD led to growth cone collapse or other inhibitory responses. These results demonstrate that, in addition to the conventional role of Eph proteins signaling as receptors, EphB receptor ECDs can also function in the opposite role as guidance cues to alter axon behavior. Furthermore, the data support a model in which dorsal retinal ganglion cell axons heading to the optic disc encounter a gradient of inhibitory EphB proteins which helps maintain tight axon fasciculation and prevents aberrant axon growth into ventral retina. In conclusion, development of neuronal connectivity may involve the combined activity of Eph proteins serving as guidance receptors and as axon guidance cues.

The metalloproteinase ADAM10 is required for retinal ganglion cell axon guidance in the developing visual systems

2007 ◽  
Vol 30 (4) ◽  
pp. 77
Author(s):  
Y. Y. Chen ◽  
C. L. Hehr ◽  
K. Atkinson-Leadbeater ◽  
J. C. Hocking ◽  
S. McFarlane
Keyword(s):  
Ganglion Cell ◽  
Axon Guidance ◽  
Retinal Ganglion Cell ◽  
Growth Cone ◽  
Expression Patterns ◽  
Optic Tract ◽  
Axon Growth ◽  
Proteolytic Processing ◽  
Retinal Ganglion

Background: The growth cone interprets cues in its environment in order to reach its target. We want to identify molecules that regulate growth cone behaviour in the developing embryo. We investigated the role of A disintegrin and metalloproteinase 10 (ADAM10) in axon guidance in the developing visual system of African frog, Xenopus laevis. Methods: We first examined the expression patterns of adam10 mRNA by in situ hybridization. We then exposed the developing optic tract to an ADAM10 inhibitor, GI254023X, in vivo. Lastly, we inhibited ADAM10 function in diencephalic neuroepithelial cells (through which retinal ganglion cell (RGC) axons extend) or RGCs by electroporating or transfecting an ADAM10 dominant negative (dn-adam10). Results: We show that adam10 mRNA is expressed in the dorsal neuroepithelium over the time RGC axons extend towards their target, the optic tectum. Second, pharmacological inhibition of ADAM10 in an in vivo exposed brain preparation causes the failure of RGC axons to recognize their target at low concentrations (0.5, 1 μM), and the failure of the axons to make a caudal turn in the mid-diencephalon at higher concentration (5 μM). Thus, ADAM10 function is required for RGC axon guidance at two key guidance decisions. Finally, molecular inhibition of ADAM10 function by electroporating dn-adam10 in the brain neuroepithelium causes defects in RGC axon target recognition (57%) and/or defects in caudal turn (12%), as seen with the pharmacological inhibitor. In contrast, molecular inhibition of ADAM10 within the RGC axons has no effect. Conclusions: These data argue strongly that ADAM10 acts cell non-autonomously within the neuroepithelium to regulate the guidance of RGC axons. This study shows for the first time that a metalloproteinase acts in a cell non-autonomous fashion to direct vertebrate axon growth. It will provide important insights into candidate molecules that could be used to reform nerve connections if destroyed because of injury or disease. References Hattori M, Osterfield M, Flanagan JG. Regulated cleavage of a contact-mediated axon repellent. Science 2000; 289(5483):1360-5. Janes PW, Saha N, Barton WA, Kolev MV, Wimmer-Kleikamp SH, Nievergall E, Blobel CP, Himanen JP, Lackmann M, Nikolov DB. Adam meets Eph: an ADAM substrate recognition module acts as a molecular switch for ephrin cleavage in trans. Cell 2005; 123(2):291-304. Pan D, Rubin GM. Kuzbanian controls proteolytic processing of Notch and mediates lateral inhibition during Drosophila and vertebrate neurogenesis. Cell 1997; 90(2):271-80.

scholarly journals Axon Guidance: Opposing EPHects in the Growth Cone

Cell ◽  
2005 ◽  
Vol 121 (1) ◽  
pp. 4-6 ◽  
Author(s):  
Rüdiger Klein
Keyword(s):  
Axon Guidance ◽  
Growth Cone

scholarly journals ERM proteins regulate growth cone responses to Sema3A

2008 ◽  
Vol 510 (4) ◽  
pp. 351-366 ◽  
Author(s):  
C. David Mintz ◽  
Ioana Carcea ◽  
Daniel G. McNickle ◽  
Tracey C. Dickson ◽  
Yongchao Ge ◽  
...  
Keyword(s):  
Growth Cone ◽  
Erm Proteins

scholarly journals Expression of Developmentally Important Axon Guidance Cues in the Adult Optic Chiasm

2019 ◽  
Vol 60 (14) ◽  
pp. 4727
Author(s):  
Raquel Conceição ◽  
Rachel S. Evans ◽  
Craig S. Pearson ◽  
Barbara Hänzi ◽  
Andrew Osborne ◽  
...  
Keyword(s):  
Axon Guidance ◽  
Optic Chiasm ◽  
Guidance Cues
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