Functional studies of type I inositol hexakisphosphate kinase and its role in cell signaling [Elektronische Ressource] / vorgelegt von Karen Abel

Functional Studies of Type I Inositol Hexakisphosphate Kinase and its Role in Cell Signaling Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften (Dr. rer. nat.) dem Fachbereich Biologie der Philipps-Universität Marburg vorgelegt von Karen Abel aus Oldenburg (Oldb) angefertigt im Department of Pharmacology University of Wisconsin Madison, USA Marburg/Lahn 2003 Vom Fachbereich Biologie der Philipps-Universität Marburg als Dissertation am 27.08.2003 angenommen. Erstgutachter: Prof. Dr. Michael Bölker Zweitgutachter: Prof. Dr. Richard A. Anderson Tag der mündlichen Prüfung am 1.9.2003 Summary Summary Inositol pentakis- and hexakisphosphates are the most abundant inositolphosphates in cells. Both inositolphosphates can be further phosphorylated by three inositol hexakisphosphate kinase isoforms (IP K1, 2 and 3) to form inositol pyrophosphates (IP and PPIP ). Those are 6 7 4the only known high energy molecules that may function as second messengers and may act as phosphate donor. The function of those second messengers remains unknown. However, it has been reported that higher inositolphosphates may play a role in nuclear signaling pathways like transcription, mRNA export and DNA repair. In this study it was shown, that endogenous IP K1 and 2 were localized to different 6compartments of the cell.