Purification and characterization of gp138, a cell surface glycoprotein involved in the sexual cell fusion of Dictyostelium discoideum.
Macrocyst formation in Dictyostelium discoideum is initiated by the fusion of cells between two opposite mating-type strains, such as NC-4 and HM1. When these cells become fusion-competent under appropriate environmental conditions, a specific protein involved in sexual cell fusion, 138 kDa, appears on the cell surface of both NC-4 and HM1 strains, as reported previously. The present study was carried out to purify and characterize this protein. The 138 kDa protein was shown to be a glycoprotein (gp138) which binds specifically to lectins, WGA, Con-A or LCA, but not to PNA, PHAE4, RCA60 or RCA120. The isoelectric point of the gp138 was determined as pH 4.5-4.9. To confirm again the previous results, a Coomassie blue-stained gel containing the 138-kDa band was cut out following the SDS-polyacrylamide gel electrophoresis, and antiserum against this band protein(s) was obtained. Fab fragments of this antiserum caused the complete inhibition of sexual fusion between NC-4 and HM1 cells.
Suzuki
K
K
Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Yanagisawa
K
K
D002459:Cell Fusion / Q000502:physiology; D004023:Dictyostelium / Q000032:analysis / Q000254:growth & development*; D005656:Fungal Proteins / Q000302:isolation & purification*; D008562:Membrane Glycoproteins / Q000302:isolation & purification* / Q000502:physiology; D008970:Molecular Weight
D005656:Fungal Proteins; D008562:Membrane Glycoproteins