Kinesin-1 Acts with Netrin and DCC to Maintain Sensory Neuron Position in Caenorhabditis elegans

The organization of neurons and the maintenance of that arrangement are critical to brain function. Failure of these processes in humans can lead to severe birth defects, mental retardation, and epilepsy. Several kinesins have been shown to play important roles in cell migration in vertebrate systems, but few upstream and downstream pathway members have been identified. Here, we utilize the genetic model organism Caenorhabditis elegans to elucidate the pathway by which the C. elegans Kinesin-1 Heavy Chain (KHC)/KIF5 ortholog UNC-116 functions to maintain neuronal cell body position in the PHB sensory neurons. We find that UNC-116/KHC acts in part with the cell and axon migration molecules UNC-6/Netrin and UNC-40/DCC in this process, but in parallel to SAX-3/Robo. We have also identified several potential adaptor, cargo, and regulatory proteins that may provide insight into the mechanism of UNC-116/KHC's function in this process. These include the cargo receptor UNC-33/CRMP2, the cargo adaptor protein UNC-76/FEZ and its regulator UNC-51/ULK, the cargo molecule UNC-69/SCOCO, and the actin regulators UNC-44/Ankyrin and UNC-34/Enabled. These genes also act in cell migration and axon outgrowth; however, many proteins that function in these processes do not affect PHB position. Our findings suggest an active posterior cell migration mediated by UNC-116/KHC occurs throughout development to maintain proper PHB cell body position and define a new pathway that mediates maintenance of neuronal cell body position.