The retinitis pigmentosa protein RP2 interacts with polycystin 2 and regulates cilia-mediated vertebrate development.
Ciliopathies represent a growing group of human genetic diseases whose etiology lies in defects in ciliogenesis or ciliary function. Given the established entity of renal-retinal ciliopathies, we have been examining the role of cilia-localized proteins mutated in retinitis pigmentosa (RP) in regulating renal ciliogenesis or cilia-dependent signaling cascades. Specifically, this study examines the role of the RP2 gene product with an emphasis on renal and vertebrate development. We demonstrate that in renal epithelia, RP2 localizes to the primary cilium through dual acylation of the amino-terminus. We also show that RP2 forms a calcium-sensitive complex with the autosomal dominant polycystic kidney disease protein polycystin 2. Ablation of RP2 by shRNA promotes swelling of the cilia tip that may be a result of aberrant trafficking of polycystin 2 and other ciliary proteins. Morpholino-mediated repression of RP2 expression in zebrafish results in multiple developmental defects that have been previously associated with ciliary dysfunction, such as hydrocephalus, kidney cysts and situs inversus. Finally, we demonstrate that, in addition to our observed physical interaction between RP2 and polycystin 2, dual morpholino-mediated knockdown of polycystin 2 and RP2 results in enhanced situs inversus, indicating that these two genes also regulate a common developmental process. This work suggests that RP2 may be an important regulator of ciliary function through its association with polycystin 2 and provides evidence of a further link between retinal and renal cilia function.
Hurd
Toby
T
Department of Pediatrics and Communicable Diseases, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA. whurd@umich.edu
Zhou
Weibin
W
Jenkins
Paul
P
Liu
Chia-Jen
CJ
Swaroop
Anand
A
Khanna
Hemant
H
Martens
Jeffrey
J
Hildebrandt
Friedhelm
F
Margolis
Ben
B
D000215:Acylation; D000818:Animals; D002923:Cilia / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005136:Eye Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins; D055785:Gene Knockdown Techniques; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism / Q000503:physiopathology; D052177:Kidney Diseases, Cystic / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009154:Mutation; D050396:TRPP Cation Channels / Q000378:metabolism*; D014714:Vertebrates / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics / Q000378:metabolism
D005136:Eye Proteins; D019204:GTP-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D050396:TRPP Cation Channels; C072178:RP2 protein, human