2. Academic Validation
  3. Nephrocystin-5, a ciliary IQ domain protein, is mutated in Senior-Loken syndrome and interacts with RPGR and calmodulin

Nephrocystin-5, a ciliary IQ domain protein, is mutated in Senior-Loken syndrome and interacts with RPGR and calmodulin

  • Nat Genet. 2005 Mar;37(3):282-8. doi: 10.1038/ng1520.
Edgar A Otto 1,  Bart Loeys,  Hemant Khanna,  Jan Hellemans,  Ralf Sudbrak,  Shuling Fan,  Ulla Muerb,  John F O'Toole,  Juliana Helou,  Massimo Attanasio,  Boris Utsch,  John A Sayer,  Concepcion Lillo,  David Jimeno,  Paul Coucke,  Anne De Paepe,  Richard Reinhardt,  Sven Klages,  Motoyuki Tsuda,  Isao Kawakami,  Takehiro Kusakabe,  Heymut Omran,  Anita Imm,  Melissa Tippens,  Pamela A Raymond,  Jo Hill,  Phil Beales,  Shirley He,  Andreas Kispert,  Benjamin Margolis,  David S Williams,  Anand Swaroop,  Friedhelm Hildebrandt
Affiliations

Affiliation

  • 1 Department of Pediatrics, University of Michigan, Ann Arbor, Michigan 48109, USA.
PMID: 15723066 DOI: 10.1038/ng1520
Abstract

Nephronophthisis (NPHP) is the most frequent genetic cause of chronic renal failure in children. Identification of four genes mutated in NPHP subtypes 1-4 (refs. 4-9) has linked the pathogenesis of NPHP to ciliary functions. Ten percent of affected individuals have retinitis pigmentosa, constituting the renal-retinal Senior-Loken syndrome (SLSN). Here we identify, by positional cloning, mutations in an evolutionarily conserved gene, IQCB1 (also called NPHP5), as the most frequent cause of SLSN. IQCB1 encodes an IQ-domain protein, nephrocystin-5. All individuals with IQCB1 mutations have retinitis pigmentosa. Hence, we examined the interaction of nephrocystin-5 with RPGR (retinitis pigmentosa GTPase regulator), which is expressed in photoreceptor cilia and associated with 10-20% of retinitis pigmentosa. We show that nephrocystin-5, RPGR and Calmodulin can be coimmunoprecipitated from retinal extracts, and that these proteins localize to connecting cilia of photoreceptors and to primary cilia of renal epithelial cells. Our studies emphasize the central role of ciliary dysfunction in the pathogenesis of SLSN.

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