Purification of a 200 kDa protein-binding protein from the fat body of Sarcophaga peregrina larvae

Previously, we demonstrated that pupal hemocytes of Sarcophaga disintegrate the larval fat body in vitro, mimicking the fat body decomposition that takes place in the pupal stage (Kurata S., Komano H. and Natori S. (1989) J. Insect Physiol. 35, 559-565), and that hemocytes expressing a 200 kDa protein appear only in the pupal stage (Kurata S., Kobayashi H. and Natori S. (1991) Dev. Biol. 146, 179-185). In the present study, we purified a protein from the larval fat body that specifically binds to the hemocyte 200 kDa protein. This binding protein consisted of 220 and 230 kDa subunits. This binding protein disappeared from the fat body within 10 h after pupation, suggesting that the hemocytes expressing the 200 kDa protein interact with the fat body via this binding protein during this period.