Identification of the 37-kDa protein displaying a variable interaction with the erythroid cell membrane as glyceraldehyde-3-phosphate dehydrogenase.
In previous studies from this laboratory we isolated and characterized a 37-kDa protein that was associated with the membrane of erythroid cells. The polypeptide appeared to undergo a lineage-specific alteration in its interaction with the membrane during erythroid development and migrated as a family of isoelectric focusing variants during analyses on two-dimensional gels. We report here that the 37-kDa protein is homologous to the enzyme glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12). This conclusion was reached from the results of several experimental approaches comparing the biochemical and genetic properties of the 37-kDa protein (p37) with authentic glyceraldehyde-3-phosphate dehydrogenase. Peptide maps of highly purified p37 and glyceraldehyde-3-phosphate dehydrogenase, generated with Staphylococcus V8 protease, were identical. The nucleotide sequence of a cDNA clone encoding p37 was nearly identical to the published sequence for genes encoding glyceraldehyde-3-phosphate dehydrogenase. These results suggest that the interaction of the enzyme with the red cell membrane is more complex than previously envisioned. The existence of subpopulations of glyceraldehyde-3-phosphate dehydrogenase molecules is envisioned that exhibit different levels of enzyme activity and bind to the red cell membrane with varying affinities.
D001483:Base Sequence; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology*; D004262:DNA Restriction Enzymes; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000032:analysis* / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics; D008970:Molecular Weight; D010449:Peptide Mapping; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics
D008565:Membrane Proteins; D012333:RNA, Messenger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D004262:DNA Restriction Enzymes