Abstract: Cell adhesion molecule gp150 plays an important role during post-aggregation stage of Dictyostelium discoideum development. The protein localization through antibodies against gp150 showed that gp150 distributed at different places during the various stages of development. In stream stage before aggregation, gp150 distributed uniformly in cytoplasm; after that, gp150 occupied the periphery region of multicellular aggregates in mound stage. During the slug stage of development, the expression level of gp150 in prestalk cells was much higher than that in prespore cells. In fruiting body stage, gp150 was enriched on the sporoderm of mature spores. High performance liquid chromatography was used to analyze PKA activity in wide-type KAx-3 cells and gp150 over expressed strain KAx-3:act15/lagC, and the results showed that, at the early stage of development (before 10 h development), PKA had lower activity in KAx-3 cells than that in KAx-3:act15/lagC cells. However, at the later stage of development, since the rapid accumulation of gp150, PKA showed higher activity in wide type cells than that in KAx-3:act15/lagCcells. These results suggested that there might be a feed back loop interaction between gp150 and PKA, by which the two signal proteins can cooperate and regular the growth and development of Dictyostelium discoideum.

Key words: fluorescence localization, gp150, PKA, HPLC