Purification, identification, and characterization of two GTP-binding proteins with molecular weights of 25,000 and 21,000 in human platelet cytosol:one is the rap1/smg21/Krev-1 protein and the other is a novel GTP-binding protein - Nagata, K; Itoh, H; Katada, T; Takenaka, K; Ui, M; Kaziro, Y; Nozawa, Y (J Biol Chem, 1989)