The thrombospondin repeat containing protein MIG-21 controls a left-right asymmetric Wnt signaling response in migrating C. elegans neuroblasts

► Polarization specifies the Wnt signaling response of the C. elegans Q neuroblasts. ► Posterior polarization sensitizes for canonical Wnt/β-catenin pathway activation. ► Polarization is dependent on the TSP repeat protein MIG-21. ► MIG-21 acts cell autonomously in the Q neuroblasts during the polarization process. ► MIG-21 functions together with the netrin receptor UNC-40/DCC.