TY - JOUR
T1 - Nerve growth factor stimulates axon outgrowth through negative regulation of growth cone actomyosin restraint of microtubule advance
AU - Turney, Stephen G.
AU - Ahmed, Mostafa
AU - Chandrasekar, Indra
AU - Wysolmerski, Robert B.
AU - Goeckeler, Zoe M.
AU - Rioux, Robert M.
AU - Whitesides, George M.
AU - Bridgman, Paul C.
N1 - Funding Information:
This research was supported by grants to P.C.B. from National Institutes of Health (R21 MH081260, R21 EB9776) and in part by the Bakewell Neuroimaging Core, an imaging facility supported by the Bakewell Family Foundation and National Institutes of Health Neuroscience Blueprint Interdisciplinary Center Core Grant P30 (NS057105) to Washington University. S.G.T. receives support from Jeff Lichtman and the Department of Molecular and Cellular Biology, Harvard University. R.B.W. was supported by grants from the National Institutes of Health (HL-090937, P20RR016440). The fabrication of microfluidics devices was performed in part at the Center for Nanoscale Systems, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation under award ECS-0335765. The Center for Nanoscale Systems is part of the Faculty of Arts and Sciences, Harvard University. R.M.R. received a postdoctoral fellowship (1 F32 NS60356-01) from the National Institutes of Health.
Publisher Copyright:
© 2016 Turney et al.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Nerve growth factor (NGF) promotes growth, differentiation, and survival of sensory neurons in the mammalian nervous system. Little is known about how NGF elicits faster axon outgrowth or how growth cones integrate and transform signal input to motor output. Using cultured mouse dorsal root ganglion neurons, we found that myosin II (MII) is required for NGF to stimulate faster axon outgrowth. From experiments inducing loss or gain of function of MII, specific MII isoforms, and vinculin-dependent adhesion-cytoskeletal coupling, we determined that NGF causes decreased vinculin-dependent actomyosin restraint of microtubule advance. Inhibition of MII blocked NGF stimulation, indicating the central role of restraint in directed outgrowth. The restraint consists of myosin IIB- And IIA-dependent processes: retrograde actin network flow and transverse actin bundling, respectively. The processes differentially contribute on laminin-1 and fibronectin due to selective actin tethering to adhesions. On laminin-1, NGF induced greater vinculin-dependent adhesion-cytoskeletal coupling, which slowed retrograde actin network flow (i.e., it regulated the molecular clutch). On fibronectin, NGF caused inactivation of myosin IIA, which negatively regulated actin bundling. On both substrates, the result was the same: NGF-induced weakening of MIIdependent restraint led to dynamic microtubules entering the actin-rich periphery more frequently, giving rise to faster elongation.
AB - Nerve growth factor (NGF) promotes growth, differentiation, and survival of sensory neurons in the mammalian nervous system. Little is known about how NGF elicits faster axon outgrowth or how growth cones integrate and transform signal input to motor output. Using cultured mouse dorsal root ganglion neurons, we found that myosin II (MII) is required for NGF to stimulate faster axon outgrowth. From experiments inducing loss or gain of function of MII, specific MII isoforms, and vinculin-dependent adhesion-cytoskeletal coupling, we determined that NGF causes decreased vinculin-dependent actomyosin restraint of microtubule advance. Inhibition of MII blocked NGF stimulation, indicating the central role of restraint in directed outgrowth. The restraint consists of myosin IIB- And IIA-dependent processes: retrograde actin network flow and transverse actin bundling, respectively. The processes differentially contribute on laminin-1 and fibronectin due to selective actin tethering to adhesions. On laminin-1, NGF induced greater vinculin-dependent adhesion-cytoskeletal coupling, which slowed retrograde actin network flow (i.e., it regulated the molecular clutch). On fibronectin, NGF caused inactivation of myosin IIA, which negatively regulated actin bundling. On both substrates, the result was the same: NGF-induced weakening of MIIdependent restraint led to dynamic microtubules entering the actin-rich periphery more frequently, giving rise to faster elongation.
UR - http://www.scopus.com/inward/record.url?scp=84956643097&partnerID=8YFLogxK
U2 - 10.1091/mbc.E15-09-0636
DO - 10.1091/mbc.E15-09-0636
M3 - Article
C2 - 26631553
AN - SCOPUS:84956643097
SN - 1059-1524
VL - 27
SP - 500
EP - 517
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 3
ER -