Nephrocystin-4 regulates Pyk2-induced tyrosine phosphorylation of nephrocystin-1 to control targeting to monocilia.
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Liebau MC, Hopker K, Muller RU, Schmedding I, Zank S, Schairer B, Fabretti F, Hohne M, Bartram MP, Dafinger C, Hackl M, Burst V, Habbig S, Zentgraf H, Blaukat A, Walz G, Benzing T, Schermer B
Nephrocystin-4 regulates Pyk2-induced tyrosine phosphorylation of nephrocystin-1 to control targeting to monocilia.
J Biol Chem. 2011 Apr 22;286(16):14237-45. doi: 10.1074/jbc.M110.165464. Epub 2011 Feb 28.
- PubMed ID
- 21357692 [ View in PubMed]
- Abstract
Nephronophthisis is the most common genetic cause of end-stage renal failure during childhood and adolescence. Genetic studies have identified disease-causing mutations in at least 11 different genes (NPHP1-11), but the function of the corresponding nephrocystin proteins remains poorly understood. The two evolutionarily conserved proteins nephrocystin-1 (NPHP1) and nephrocystin-4 (NPHP4) interact and localize to cilia in kidney, retina, and brain characterizing nephronophthisis and associated pathologies as result of a ciliopathy. Here we show that NPHP4, but not truncating patient mutations, negatively regulates tyrosine phosphorylation of NPHP1. NPHP4 counteracts Pyk2-mediated phosphorylation of three defined tyrosine residues of NPHP1 thereby controlling binding of NPHP1 to the trans-Golgi sorting protein PACS-1. Knockdown of NPHP4 resulted in an accumulation of NPHP1 in trans-Golgi vesicles of ciliated retinal epithelial cells. These data strongly suggest that NPHP4 acts upstream of NPHP1 in a common pathway and support the concept of a role for nephrocystin proteins in intracellular vesicular transport.