Rab1a rescues the toxicity of PRAF3.

The PRA1-superfamily member PRAF3 plays pivotal roles in membrane traffic as a GDI displacement factor via physical interaction with a variety of Rab proteins, as well as in the modulation of antioxidant glutathione through its interaction with EAAC1 (SLC1A1). Overproduction of PRAF3 is known to be toxic to the host cells, although the factors capable of cancelling the toxicity remained unknown. We here show that Rab1a can rescue the cytotoxicity caused by PRAF3 possibly by "positively" regulating ER-Golgi trafficking, cancelling the "negative" modulation by PRAF3. Our results illuminate the close physiological relationship between PRAF3 and Rab proteins.