Cell surface oligosaccharides participate in cohesion during aggregation of Dictyostelium discoideum.
Plasma membrane glycoproteins from Dictyostelium discoideum amoebae at three stages of early development were digested with Pronase and endoglycosidase H and fractionated by gel filtration. This gave three classes of glycans (polysaccharides, endoglycosidase H-resistant glycopeptides, and endoglycosidase H-released oligosaccharides), which were tested for their ability to block agglutination of amoebae from vegetative, aggregation (8-hr), and late-aggregation (13-hr) stages of development. The endoglycosidase H-resistant glycopeptides from 8-hr cells inhibited agglutination of disaggregated 8-hr cells but not vegetative or 13-hr cells. The 8-hr polysaccharide and endo H-sensitive oligosaccharides did not inhibit. The glycopeptides from 8-hr cells were resolved into five species by electrophoresis in borate-containing buffer. Two of these had agglutination-inhibiting activity, and three did not. None of the glycan fractions from vegetative or 13-hr cells inhibited agglutination of vegetative, 8-, or 13-hr cells. These data implicate specific cell surface glycans in aggregation-stage intercellular cohesion and suggest that both these glycans and receptors for them are developmentally regulated.
Department of Biology, Georgetown University, Washington, DC 20057.
S E
SE
Ziska
E J
EJ
Henderson
D002449:Cell Aggregation / Q000187:drug effects; D004023:Dictyostelium / Q000502:physiology*; D005656:Fungal Proteins / Q000502:physiology; D006023:Glycoproteins / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology; D011134:Polysaccharides / Q000494:pharmacology / Q000502:physiology*
D005656:Fungal Proteins; D006023:Glycoproteins; D008565:Membrane Proteins; D010446:Peptide Fragments; D011134:Polysaccharides