Online supplemental material Fig. S1 shows zebrafish rpgrip1l gene expression. Fig. S2 shows no apparent defect in dorso–ventral (DV) and antero–posterior (AP) patterning, and in cilium and basal body integrity, in rpgrip1l morphants. Fig. S3 shows interaction of rpgrip1l with PCP genes and with inversin. Fig. S4 shows cilium and basal body integrity in MDCK cells upon RPGRIP1L depletion. Fig. S5 shows RPGRIP1L depletion in MDCK cells: rescue and dishevelled localization at the membrane.