Biochemical characterization of the phagocytic giant cell receptor for Dictyostelium discoideum amoebae: identification by cell blotting.

A critical aspect of sexual development in Dictyostelium is the selection of "self" as a targeted food source by the phagocytic zygotic giant cell (ZGC). It has previously been demonstrated that phagocytic giant cells preferentially take up amoebae of the same species suggesting that the process is mediated by a specific receptor. By using tunicamycin, which inhibits N-linked glycosylation and mevastatin and mevinolin, which both inhibit HMG-CoA-reductase, we have been able to further characterize the glycoprotein(s) involved in the recognition process. We have utilized a "cell blotting" technique which lends itself well to identifying glycoproteins which are present on the ZGC at the phagocytic stage and interactive with the target amoebae. The cell blotting data, combined with pharmacological evidence, identifies these glycoproteins as the receptors for cannibalistic phagocytosis by the ZGC of D. discoideum.