Cell-surface discoidin in aggregating cells of Dictyostelium discoideum.
Both discoidin I and discoidin II have been detected on the surface of aggregating (10 h developmental stage) cells of Dictyostelium discoideum NC4 by radioiodination of the cell-surface followed by immunoprecipitation and sodium dodecyl sulphate/polyacrylamide-gel-electrophoretic analysis. Approx. 92% of cell-surface discoidin I and 72% of cell-surface discoidin II can be eluted with 0.5 M-galactose, showing that most of each endogenous lectin is not present as integral membrane protein but rather is bound to cell-surface discoidin receptors. Two-dimensional polyacrylamide-gel-electrophoretic analysis of discoidin I suggests that the native tetramer may be a hetero-multimer composed of both Ia and Ib subunits. Cell-surface discoidin I also contains both types of subunit, but it is not clear whether both subunits have corresponding cell-surface receptors.
D002352:Carrier Proteins / Q000032:analysis*; D002449:Cell Aggregation; D002462:Cell Membrane / Q000032:analysis; D004023:Dictyostelium / Q000032:analysis*; D000070821:Discoidins; D004591:Electrophoresis, Polyacrylamide Gel; D007457:Iodine Radioisotopes; D037102:Lectins / Q000032:analysis*; D008565:Membrane Proteins / Q000378:metabolism; D015800:Protozoan Proteins
D002352:Carrier Proteins; D000070821:Discoidins; D007457:Iodine Radioisotopes; D037102:Lectins; D008565:Membrane Proteins; D015800:Protozoan Proteins