PIEZO1 and Bardet-Biedl syndrome: To test this we tagged the inwardly rectifying potassium Kir2.1 channel with a BBS (Kir2.1-BBS) on the first extracellular pore loop (S1-pore helix) and co-expressed it with wild-type Piezo1-pIRES-EGFP in HEK293T cells (Fig. 3f; Supplementary Fig. 9).