title: Anks3 alters the sub-cellular localization of the Nek7 kinase.
abstract: Nephronophthisis (NPH) is an autosomal recessive cystic kidney disease, and a frequent cause of end-stage renal failure in children. To date, 17 NPH-associated gene products (NPHPs) have been identified. Most NPHPs participate in large multi-protein complexes that localize to the cilium and/or basal body; however, the precise composition of these complexes and their biological function remain largely unknown. We recently observed that the ankyrin repeat protein Anks3 interacts with the NPH family member Anks6. Both Anks3 and Anks6 form complexes with multiple other NPHPs, suggesting that both proteins function in similar or overlapping signaling pathways. Here, we show that Anks3, but not Anks6 interacted with the NIMA-related kinase Nek7, and was heavily modified in the presence of Nek7, resulting in an approximately 20 kD increase in molecular weight. Although mass spectrometry revealed increased serine and threonine phosphorylation of Anks3 primarily within the N-terminal ankyrin repeats also required for Nek7 interaction, the molecular weight increase occurred even in the presence of a kinase-dead Nek7 mutant, indicating that this modification was not caused by Nek7-dependent Anks3 phosphorylation. Furthermore, the Anks3 modification was specific for Nek7, and did not occur in the presence of Nek8. Importantly, Anks3 retained Nek7 in the cytoplasm, suggesting that, Nek7 triggers the modification of Anks3, which in turn prevents the nuclear localization of Nek7.
authors.affiliation: Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany.
authors.forename: Haribaskar
authors.initials: H
authors.lastname: Ramachandran
authors.affiliation: Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Engel
authors.affiliation: Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Müller
authors.affiliation: Department of Dermatology, University Freiburg Medical Center and Center of Biological Systems Analysis, Habsburgerstr. 49, 79104 Freiburg, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Dengjel
authors.affiliation: Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany; Center for Biological Signaling Studies (BIOSS), Albertstr. 19, 79104 Freiburg, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Walz
authors.affiliation: Renal Division, Department of Medicine, University Freiburg Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany. Electronic address: toma.antonov.yakulov@uniklinik-freiburg.de.
authors.forename: Toma A
authors.initials: TA
authors.lastname: Yakulov
mesh_terms: D000818:Animals; D017089:Ankyrin Repeat; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D046912:Multiprotein Complexes / Q000378:metabolism; D009154:Mutation; D000072379:NIMA-Related Kinases; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D012694:Serine / Q000378:metabolism; D013912:Threonine / Q000378:metabolism; D014162:Transfection
chemical_list: C000595708:ANKS3 protein, human; C000602533:Anks3 protein, mouse; C532259:Anks6 protein, rat; D002352:Carrier Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D013912:Threonine; D012694:Serine; D011494:Protein Kinases; C512685:NEK7 protein, human; C458529:NEK8 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases
keywords: Ankyrin repeat proteins; Ciliopathies; Kinase; Nephronophthisis