Figure 3 – Polycystin channels protect the kidney from cystogenesis.
A) Polycystin channels are heterotetramers each comprised of one PKD1 subunit and three PKD2 subunits. Image of PDB 6A70 human PKD1/PKD2 complex (Su et al., 2018) created with UCSF ChimeraX. B) Almost all nephron epithelial cells project a Polycystin channel-bearing cilium into the lumen through which filtrate flows. C) Removing cilia from nephron epithelial cells causes mild cystogenesis. Removing Polycystin function by abrogating either PKD1 or PKD2 causes severe cystogenesis. Removing both cilia and Polycystin function causes moderate cystogenesis, revealing cilia-dependent cyst activation (CDCA) (Ma et al., 2013).