Zinc ions and alkaline pH alter the phosphorylated state of proteins 3 and 4.2 in human erythrocyte membranes.
The phosphorylation patterns of isolated red blood cell (RBC) membranes labeled with [gamma-32P] ATP are altered by Zn++ ions. Zn++ ions caused an increased phosphate incorporation into a 72 KDa protein and several proteins in the 40-60 KDa region and a decrease in the labeling of a 53 KDa protein. The 72 KDa and 53 KDa proteins have been identified as protein 4.2 and a protease-cleaved fragment of protein 3, respectively. Evidence suggests that the changes in phosphorylation pattern may be due to the stimulation of endogenous membrane alkaline phosphatase(s). Our results suggest that Zn++, at physiological concentrations in the intact erythrocyte, could modulate the phosphorylation of selected proteins which may regulate their association in the cytoskeletal network.
Fennell
R L
RL
Department of Biological Chemistry, Hahnemann University, Philadelphia, PA 19102.
Soslau
G
G
D000469:Alkaline Phosphatase / Q000032:analysis; D001457:Anion Exchange Protein 1, Erythrocyte / Q000737:chemistry*; D001798:Blood Proteins / Q000737:chemistry*; D003598:Cytoskeletal Proteins; D004910:Erythrocyte Membrane / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008565:Membrane Proteins; D008970:Molecular Weight; D010449:Peptide Mapping; D010766:Phosphorylation / Q000187:drug effects; D015032:Zinc / Q000494:pharmacology*
D001457:Anion Exchange Protein 1, Erythrocyte; D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D007477:Ions; D008565:Membrane Proteins; C044791:erythrocyte membrane band 4.2 protein; D000469:Alkaline Phosphatase; D015032:Zinc