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Wheat germ agglutinin binds to the contact site A glycoprotein of Dictyostelium discoideum and inhibits EDTA‐stable cell adhesion
Author(s) -
Yoshida M.,
Stadler J.,
Bertholdt G.,
Gerisch G.
Publication year - 1984
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1984.tb02191.x
Subject(s) - planck , dictyostelium discoideum , physics , biology , stereochemistry , chemistry , biochemistry , quantum mechanics , gene
Wheat germ agglutinin (WGA), a lectin that primarily reacts with N‐acetylglucosamine residues, specifically inhibits the EDTA‐stable type of intercellular adhesion of aggregation competent Dictyostelium discoideum cells. The major WGA‐binding protein of these cells is a developmentally‐regulated glycolipoprotein of 80 kd apparent mol. wt., designated as contact site A. This glycoprotein is a target site of antibody fragments that block the EDTA‐stable cell adhesion, and is characterized by sulfated carbohydrate residues. WGA does not significantly bind to glycoproteins of a mutant, HL220, which produces a 68‐kd component in place of the 80‐kd glycoprotein. Inhibition of N‐glycosylation by tunicamycin causes wild‐type cells to produce a WGA‐binding but unsulfated 66‐kd component and a non‐binding 53‐kd component. These results indicate that the 80‐kd glycoprotein contains two classes of carbohydrate residues, a WGA‐binding one that is defective in HL220, and another, sulfated, one that is absent from the 66‐kd wild‐type product; both are missing in the 53‐kd protein. WGA and a monoclonal antibody that is blocked by N‐acetylglucosamine were further used to probe for glycoproteins in the multicellular slug stage that share carbohydrate structures – and possibly functions – with the contact site A glycoprotein. Glycoproteins in the 95‐kd range have previously been implicated in cell‐to‐cell adhesion during the slug stage. We distinguished a 95‐kd glycoprotein that binds WGA from another one that binds antibody.