Table 2.
FGF signaling during axon development and function
| FGFs | FGFRs | Signaling Pathways | Role in axon | Biological Function | Model | Ref |
|---|---|---|---|---|---|---|
| FGF2 | FGFR1 | - | Axon outgrowth/Axon branching | Promotes axonal elongation and branching in cultured DRGs neurons | Rat | [53, 54, 57] |
| - | - | Axon branching | Promotes mainly interstitial branching of cortical axons in vitro | M.auratus | [55] | |
| - | MAPK/Erk (?) | Axon branching | Enhances the severing of MTs in hippocampal neurons through expression of katanin and spastin | Rat | [58] | |
| - | - | Inhibition of axon branching | Suppresses axonal branching in cultured hippocampal granule neurons | Rat | [60] | |
| - | PLC | Axon guidance | Chemorepulsive effect on RGCs growth cones | Xen | [27] | |
| - | - | Presynaptic formation | Induces presynaptic vesicle clustering | Xen/Rat | [81, 82] | |
| FGF3 | FGFR1 (?) | - | Axon guidance | Attracts hypothalamic axons towards the neurohypophysis | Chick/Zeb | [75] |
| FGF4 | FGFR1/Neuritin | - | Axon branching | Enhance axonal branching of cultured hippocampal granule neurons | Rat | [60] |
| FGF5 | - | - | ||||
| FGF7 | - | - | ||||
| FGFR2b | - | NMJ formation | Promotes NMJ formation by increasing vesicle clustering in motor neurons | Mouse | [84, 85] | |
| FGFR2b | - | Presynaptic formation | Promotes inhibitory synapse formation in hippocampal neurons by increasing synaptic vesicle clustering | Mouse | [86] | |
| FGF8 | - | NFKB | Axon outgrowth | Promotes neurite outgrowth of cultured cochlear spiral ganglion neurons | Mouse | [62] |
| - | - | Axon branching | Promotes axonal branching of culture hippocampal granule neurons | Rat | [60] | |
| - | - | Axon guidance (?) | Induces the expression of slit1 and sema3A | Xen | [71] | |
| - | - | Axon guidance | Attracts trochlear motor axons from the hindbrain towards the isthmic organizer | Chick/Rat | [76] | |
| - | - | Axon guidance | Regulates growth of midbrain dopaminergic axons by inducing sema3F | Rat | [77] | |
| FGF10 | - | - | Axon guidance | Regulates growth of hypothalamic axons towards the neurohypophysis | Chick | [75] |
| FGFR2b | - | NMJ formation | Promotes NMJ formation by increasing vesicle clustering in motor neurons | Mouse | [84, 85] | |
| FGF12 | - | - | Action potential generation | Regulates AIS-localized VGSC currents | Rat | [97] |
| FGF13 | - | - | Axon specification | Induces MTs polymerization and stabilization in the growth cone | Rat/Mouse | [52] |
| FGF14 | - | - | Action potential generation | Regulates AIS-localization and currents of VGSC and KCNQ channels | Mouse/Rat | [91] |
| - | - | Action potential generation | Regulates presynaptic calcium channel currents | Mouse/Rat | [94] | |
| FGF22 | FGFR2b | - | NMJ formation | Promotes NMJ formation by increasing vesicle clustering in motor neurons | Mouse | [84, 85] |
| FGFR2b | PI3K/Akt (?) | Presynaptic formation | Promotes excitatory synapse formation in hippocampal neurons by increasing synaptic vesicle clustering | Mouse | [86, 88] | |
| FGFR1b | - | |||||
| - | FGFR1 | PI3K-Akt | Axon guidance | Regulates slit1 levels in the forebrain | Xen | [72, 73] |
| - | - | Axon guidance | Required for the targeting of GNRH1 axons to the median eminence | Mouse | [74] | |
| - | - | Axon guidance | Required for the growth of MMCm axons towards FGF-producing somites | Mouse | [78] | |
| FGFR2-4 | PI3K-Akt | Axon guidance | Regulate sema3A expression in the forebrain | Xen | [73] |
AIS Axon initial segment, DRG Dorsal root ganglia, GNRH1 Gonadotropin-releasing hormone, KCNQ Voltage-gated potassium channels, M.auratus Mesocricetus auratus, MTs Microtubules, MMCm Spinal motor neurons from the medial class, NMJ Neuromuscular junction, RGC Retinal ganglion cell, Sema Semaphorin, VGSC Voltage-gated sodium channels, Xen Xenopus laevis, Zeb Zebrafish