Identification and purification of the cell surface glycoprotein homologous to PsA in different species of cellular slime mold on the basis of a shared carbohydrate epitope

Abstract

AbstractThe monoclonal antibodies MUD1 and MUD50 recognize peptide and carbohydrate epitopes, respectively, on the Dictyoste‐lium discoideum developmentally regulated cell surface glycoprotein PsA. PsA is a putative pre‐spore cell adhesion molecule during the slug stage and is anchored to the cell membrane via a phos‐phatidylinositol glycan. Here we report on the presence of a PsA‐like homolog in several Dictyo‐stelium species. The MUD1 epitope is mostly confined to the D. discoideum complex, and only one non‐D. discoideum strain reacted strongly with this antibody. By contrast, the mAb MUD50 recognises a homologous molecule in several Dictyostelium species that do not react with MUD1. With mAb MUD50 immunoaffinity chromatography, it was possible to purify and obtain an amino‐terminal sequence for the PsA homolog from the Dictvoste‐lium sp. strain ZA3A and from one strain of D. pur‐pureum.