Figure 7.
Schematic model for UNC-51 kinase-mediated motor–cargo assembly Our results suggest a model in which UNC-51 kinase functions in axonal transport via the kinesin-1-dependent pathway. When phosphorylated by UNC-51 kinase, UNC-76, a KHC adaptor and a potential activator of kinesin-1, displays an increased affinity to SV membrane proteins such as Syt-1. UNC-51 likely phosphorylates additional substrates that are essential for axonal transport (dashed arrow). Loss or attenuation of UNC-51 kinase activity would result in a lower affinity of UNC-76 to SV membrane proteins and dissociation of SV cargoes from the motor complexes, as might be the case at NMJ. Kinesin-3 (imac/UNC-104) is also responsible for SV transport in a large fraction and is important for carrying SVs from neuronal soma to axons and synapses (red arrow).