Identifikation und Charakterisierung von Interaktionspartnern des Zystennierenproteins DZIP1L

Abstract

Polycystic kidney diseases are the most common genetic disorders; the underlying pathomechanisms are incompletely understood so far. One of the involved in the formation of cystic kidneys genes is DZIP1L. DZIP1L has previously been identified in our group as a new gene for polycystic kidney disease by homozygosity mapping of a family with autosomal recessive polycystic kidney disease. It encodes a homolog of the iguana protein in zebrafish, which is involved in the development of the pronephros and plays a role in the hedgehog signaling pathway. Term of this doctoral thesis was the identification of interaction partners of DZIP1L by a bacterial Two Hybrid system to further characterize the function and role of the protein in the cell. Coimmunoprecipitation experiments and immunfluorescence studies in transiently transfected COS7-, HEK293- and mIMCD-3- cells have been performed for validation of the interaction of DZIP1L with EEF1G, NAGK and PSAP. All three identified binding partners are involved in SMAD-/TGF-ß- signaling. NAGK and PSAP are known to directly interact with R-Smads, whereas for EEF1G an interaction with SnoN has been described. SnoN on his part interacts with an R-Smad too. Consequently, the transcription of TGF-ß target genes will be repressed. Overall, it can be postulated that DZIP1L does not only play a role in hedgehog-signaling but also influences cyst formation through modification of TGF-ß-signaling