GANAB

Cilia effects upon perturbation of GANAB

Loss-of-function effect:

No effect

Ciliogenesis screen results (3 screens)

• Wheway et al. 2015 (siRNA) [siRNA]: No effect PMID:26167766
• Breslow et al. 2018 (CRISPR) [CRISPR]: No Significant Effect PMID:29459680
• Roosing et al. 2015 (siRNA) [siRNA]: No effect PMID:26595381

Phenotypes

Human ciliopathy phenotype:

polycystic kidney disease 3 with or without polycystic liver disease; kidney disease; Autosomal dominant polycystic kidney disease; autosomal dominant polycystic liver disease; Isolated polycystic liver disease

Ciliopathy associations

• Polycystic Liver Disease
• Autosomal Dominant Polycystic Kidney Disease

Subcellular localization

cilia associated gene, lysosomes

Functional category

• Ciliary assembly/disassembly
• Viral interactions
• Protein processing & maturation
• Signaling (Hedgehog, GPCRs, ion channels)

Function

Mutations in the GANAB gene cause Autosomal Dominant Polycystic Kidney Disease (PMID: 27259053). From the genetic studies, mutations in GANAB were shown to be a cause of ADPKD and ADPLD, so we next explored the mechanism of pathogenesis by cellular analysis. CRISPR/Cas9 targeting of GANAB exon 12 in human RCTE cells generated clones with biallelic frameshift mutations (null, clone C6) or a single in-frame deletion (heterozygous, E4) (Figures S4A–S4D). Analysis of the polycystin complex immunocaptured with PC2 or PC1-CT antibodies in GANAB−/− cells showed that the PC1 N-terminal, mature product (PC1-NTR) was absent (Figures 4A and 4B). In contrast, full-length (GPS-uncleaved) PC1, PC1-NTS, and PC2 were elevated, indicating that GIIα plays a major role in PC1 maturation. We previously showed an interdependence of PC1 and PC2 for localization, including to cilia,15 and so to assess localization of the polycystin complex, we analyzed PC2. Ciliary localization of PC2 was completely absent in GANAB−/− cells, although cilia formed normally (Figure 4C and Figure S4E).15, 16 Given that affected individuals harbored just one GANAB mutation, we assayed GANAB+/− cells and found a proportional, ∼50%, depletion of PC1-NTR (Figures 4D and 4E). Analysis of the maturation of other membrane proteins (epidermal growth factor receptor [EGFR] and E-cadherin) showed that they were not (or only mildly) affected by loss of GIIα (Figure 4A). (27259053)