1. M. Amano, K. Chihara, T. Matsui, Y. Hamajima, K. Kaibuchi, Division of Signal Transduction, Nara Institute of Science and Technology, Ikoma 630-01, Japan.
2. H. Mukai and Y. Ono, Department of Biology, Faculty of Science, Kobe University, Kobe 657, Japan.
3. K. Okawa and A. Iwamatsu, Central Laboratories for Key Technology, Kirin Brewery Company Limited, Yokohama 236, Japan.