Growth Cone MKK7 mRNA Targeting Regulates MAP1b-Dependent Microtubule Bundling to Control Neurite Elongation
Figure 10
Model of localized JNK signaling during neurite elongation.
In the undifferentiated state, in the absence of growth cones, RNP-tethered, most likely 3′-UTR1 and 3′-UTR2 containing MKK7 mRNAs remain in a translation incompetent state. A somal MKK7 mRNA pool, most likely containing the 3′-UTR1 sequence, might allow production of the cytosolic MKK7 protein pool that can be engaged for stress responses. During neurite initiation, MKK7 mRNA containing RNPs are transported to the growth cone where local translation occurs. Local MKK7 synthesis and its phosphorylation by DLK allows to switch on JNK1, MAP1b phosphorylation, and mt bundling to ultimately allow neurite elongation.