Differences in accumulation and phosphorylation of proteins in vegetatively growing and aggregation-competent cells of Dictyostelium discoideum.
A comparison of proteins from whole cell lysates of vegetative amoebae and aggregation-competent cells by high-resolution two-dimensional gel electrophoresis coupled with a sensitive silver staining method revealed distinct differences. In aggregation-competent cells, 16 proteins present in the vegetative amoebae disappeared, and 25 new proteins appeared. A few other proteins showed quantitative variation during the transition of vegetative amoebae to aggregation competence. Identification of phosphoproteins by in vivo labeling with [32P]orthophosphate showed that none of the developmentally regulated cellular proteins were modified. Phosphorylation was observed in four proteins. One protein was phosphorylated exclusively in aggregation-competent cells. The phosphorylation level of two other proteins was higher in aggregation-competent cells compared with vegetative amoebae. The data suggest that phosphorylation of cellular and certain ribosomal proteins may be regulated coordinately in Dictyostelium discoideum.
Ramagopal
S
S
Department of Biochemistry, Roche Institute of Molecular Biology, Nutley, NJ 07110.
D000818:Animals; D002449:Cell Aggregation / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D004023:Dictyostelium / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D010766:Phosphorylation; D011506:Proteins / Q000378:metabolism*; D016622:Silver Staining
D011506:Proteins