Interaction of tissue transglutaminase with nuclear transport protein importin-alpha 3

Tissue transglutaminase is a multifunctional enzyme which has been involved in the regulation of cell growth, differentiation, and apoptosis, Recently , nuclear localization of tTG has been reported indicating the potential of active nuclear transport, In this study we use the yeast two-hybrid assay and coimmunoprecipitation to show that tTG interacts with the nuclear trans port protein importin-alpha 3. Using electron microscopy we demonstrate tha t nuclear expression of tTG in a non-small cell lung cancer cell line is in duced by retinoic acid (RA), These data suggest that importin-alpha 3 could mediate active nuclear transport of tTG which may be important for the reg ulation of critical cellular processes. (C) 1999 Federation of European Bio chemical Societies.