title: Erythropoietin rapidly alters phosphorylation of pp43, an erythroid membrane protein.
abstract: The phosphorylation of a prominent 43-kDa phosphoprotein (pp43) in the membranes of normal murine erythroid cells was reduced markedly by exposure of the membranes to highly purified erythropoietin. A virtually identical reduction of pp43 phosphorylation was seen when erythropoietin-responsive Rauscher murine erythroleukemia cell membranes were exposed to the hormone. This effect was both time-dependent, occurring within 30 min after erythropoietin exposure, and concentration-dependent. Phosphoamino acid analysis revealed that pp43 is phosphorylated on serine residues. The results provide the first evidence that rapid alterations in membrane protein phosphorylation may serve as a trans-membrane signal for erythropoietin.
authors.forename: H S
authors.initials: HS
authors.lastname: Choi
authors.forename: D M
authors.initials: DM
authors.lastname: Wojchowski
authors.forename: A J
authors.initials: AJ
authors.lastname: Sytkowski
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004921:Erythropoietin / Q000494:pharmacology*; D007700:Kinetics; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism; D008565:Membrane Proteins / Q000097:blood*; D051379:Mice; D010750:Phosphoproteins / Q000097:blood*; D010766:Phosphorylation; D010768:Phosphoserine / Q000097:blood; D013154:Spleen / Q000166:cytology
chemical_list: D008565:Membrane Proteins; D010750:Phosphoproteins; D004921:Erythropoietin; D010768:Phosphoserine; D000255:Adenosine Triphosphate