During Caenorhabditis elegans development, the HSN neurons and the right Q neuroblasts and its descendents undergo long-range anteriorly directed migrations. Both of these migrations require EGL-20, a C. elegans Wnt homolog. Through a canonical Wnt signaling pathway, EGL-20/Wnt transcriptionally activates the Hox gene
mab-5 in the left Q neuroblast and its descendants, causing the cells to migrate posteriorly. In this report, we show that CAM-1, a Ror receptor tyrosine kinase (RTK) family member, inhibits EGL-20 signaling. Increased levels of EGL-20, like loss of
cam-1, caused the HSNs to migrate too far anteriorly. Increased levels of CAM-1, like loss of
egl-20, shifted the final positions of the HSNs posteriorly and cause the left Q neuroblast descendants to migrate anteriorly. The reversal in the migration of the left Q neuroblast and its descendants resulted from a failure to express
mab-5, an
egl-20 mutant phenotype. Our data suggests that CAM-1 negatively regulates EGL-20.