Abstract
The mechanism by which extracellular cues influence intracellular biochemical cascades that guide axons is important, yet poorly understood. Because of the mechanical nature of axon extension, we explored whether the physical interactions of growth cones with their guidance cues might be involved. In the context of mouse spinal commissural neuron axon attraction to netrin-1, we found that mechanical attachment of netrin-1 to the substrate was required for axon outgrowth, growth cone expansion, axon attraction and phosphorylation of focal adhesion kinase (FAK) and Crk-associated substrate (CAS). Myosin II activity was necessary for traction forces >30 pN on netrin-1. Interestingly, while these myosin II-dependent forces on netrin-1 substrates or beads were needed to increase the kinase activity and phosphorylation of FAK, they were not necessary for netrin-1 to increase CAS phosphorylation. When FAK kinase activity was inhibited, the growth cone's ability to recruit additional adhesions and to generate forces >60 pN on netrin-1 was disrupted. Together, these findings demonstrate an important role for mechanotransduction during chemoattraction to netrin-1 and that mechanical activation of FAK reinforces interactions with netrin-1 allowing greater forces to be exerted.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Validation Study
MeSH terms
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Actins / metabolism
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Animals
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Axons / drug effects
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Axons / physiology*
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Cell Line, Transformed
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Crk-Associated Substrate Protein / genetics
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Crk-Associated Substrate Protein / metabolism
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Electroporation
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Embryo, Mammalian
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Enzyme Inhibitors / pharmacology
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Enzyme-Linked Immunosorbent Assay
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Female
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Focal Adhesion Protein-Tyrosine Kinases / genetics
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Focal Adhesion Protein-Tyrosine Kinases / metabolism*
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Growth Cones / physiology
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Heparin / pharmacology
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Humans
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Luminescent Proteins / genetics
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Male
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Mechanotransduction, Cellular / drug effects
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Mechanotransduction, Cellular / physiology*
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Mice
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Myosin Type II / metabolism
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Nerve Growth Factors / chemistry
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Nerve Growth Factors / genetics
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Nerve Growth Factors / metabolism*
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Netrin-1
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Neurons / cytology
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Neurons / drug effects
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Neurons / physiology*
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Organ Culture Techniques
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Phosphoproteins / metabolism
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Physical Stimulation
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Protein Binding / genetics
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Protein Structure, Tertiary / genetics
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Protein Structure, Tertiary / physiology
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Protein Transport / genetics
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Quinolones / pharmacology
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Spinal Cord / cytology
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Sulfones / pharmacology
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Transfection
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Tumor Suppressor Proteins / chemistry
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism*
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Tyrosine / metabolism
Substances
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6-(4-(3-(methylsulfonyl)benzylamino)-5-(trifluoromethyl)pyrimidin-2-ylamino)-3,4-dihydroquinolin-2(1H)-one
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Actins
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Crk-Associated Substrate Protein
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Enzyme Inhibitors
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Luminescent Proteins
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NTN1 protein, human
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Nerve Growth Factors
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Ntn1 protein, mouse
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Phosphoproteins
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Quinolones
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Sulfones
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Tumor Suppressor Proteins
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Netrin-1
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Tyrosine
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Heparin
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Focal Adhesion Protein-Tyrosine Kinases
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Myosin Type II