Nephrocystin-1 forms a complex with polycystin-1 via a polyproline motif/SH3 domain interaction and regulates the apoptotic response in mammals.
Mutations in PKD1, the gene encoding for the receptor Polycystin-1 (PC-1), cause autosomal dominant polycystic kidney disease (ADPKD). The cytoplasmic C-terminus of PC-1 contains a coiled-coil domain that mediates an interaction with the PKD2 gene product, Polycystin-2 (PC-2). Here we identify a novel domain in the PC-1 C-terminal tail, a polyproline motif mediating an interaction with Src homology domain 3 (SH3). A screen for interactions using the PC-1 C-terminal tail identified the SH3 domain of nephrocystin-1 (NPHP1) as a potential binding partner of PC-1. NPHP1 is the product of a gene that is mutated in a different form of renal cystic disease, nephronophthisis (NPHP). We show that in vitro pull-down assays and NMR structural studies confirmed the interaction between the PC-1 polyproline motif and the NPHP1 SH3 domain. Furthermore, the two full-length proteins interact through these domains; using a recently generated model system allowing us to track endogenous PC-1, we confirm the interaction between the endogenous proteins. Finally, we show that NPHP1 trafficking to cilia does not require PC-1 and that PC-1 may require NPHP1 to regulate resistance to apoptosis, but not to regulate cell cycle progression. In line with this, we find high levels of apoptosis in renal specimens of NPHP patients. Our data uncover a link between two different ciliopathies, ADPKD and NPHP, supporting the notion that common pathogenetic defects, possibly involving de-regulated apoptosis, underlie renal cyst formation.
Wodarczyk
Claas
C
Division of Genetics and Cell Biology, Dulbecco Telethon Institute at Dibit, San Raffaele Scientific Institute, Milan, Italy.
Distefano
Gianfranco
G
Rowe
Isaline
I
Gaetani
Massimiliano
M
Bricoli
Barbara
B
Muorah
Mordi
M
Spitaleri
Andrea
A
Mannella
Valeria
V
Ricchiuto
Piero
P
Pema
Monika
M
Castelli
Maddalena
M
Casanova
Ariel E
AE
Mollica
Luca
L
Banzi
Manuela
M
Boca
Manila
M
Antignac
Corinne
C
Saunier
Sophie
S
Musco
Giovanna
G
Boletta
Alessandra
A
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003598:Cytoskeletal Proteins; D004285:Dogs; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D016891:Polycystic Kidney, Autosomal Dominant / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D050396:TRPP Cation Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D010455:Peptides; D050396:TRPP Cation Channels; C108725:NPHP1 protein, human; C534985:Nphp1 protein, mouse; C011083:polyproline