Detection and identification of transcription factors as interaction partners of alien in vivo.

Interacting proteins are often involved in the same cellular processes, and thus the identification of interacting partners of a given protein with unknown function may give insight into the physiological role of this protein. For the detection of protein-protein interactions of the corepressor Alien we used a proteomic approach comprising mass spectrometry and immunological techniques. We assessed solely endogenously expressed proteins. In this study we present for the first time that Alien is interacting within a network of proteins involved in transcriptional regulation, DNA repair, and cell cycle in vivo. In this way we detected protein interactions of Alien involving nucleophosmin, ERCC3, TRIP11, as well as CRSP3.