Secreted heat shock proteins in sunflower suspension cell cultures.

Sunflower suspension cell cultures were subjected to different heat treatments and the electrophoretic patterns of heat-induced endocellular and secreted proteins were analyzed. In response to heat shock (3 h at 40°C), sunflower cells synthesized new polypeptides and secreted them into the medium, while the synthesis of other polypeptides was suppressed. Two major polypeptides of about 50 and 32 kDa were strongly induced. The two-dimensional electrophoretic analysis showed that the 32-kDa band is composed of at least four different polypeptides. Western blotting hybridizations of secreted proteins with various lectins were performed. The 32-kDa band gave a positive signal with concanavalin A.