Premium
Membrane Proteins Synthesized by Human Reticulocytes and their Precursors
Author(s) -
Krasnow S. H.,
Pielichowski H. J.,
Caro J.,
Burka E. R.,
Ballas S. K.
Publication year - 1981
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1981.tb02777.x
Subject(s) - spectrin , band 3 , membrane protein , membrane , biochemistry , polyacrylamide gel electrophoresis , gel electrophoresis , reticulocyte , in vitro , methionine , peripheral membrane protein , protein biosynthesis , intracellular , biology , microbiology and biotechnology , chemistry , amino acid , cell , integral membrane protein , enzyme , rna , cytoskeleton , gene
S ummary . Membrane protein synthesis in human immature erythroid cells was studied by incubating the cells with 5 S‐methionine in vitro. The radioactive precursor amino acid was incorporated into membrane protein in a linear fashion for approximately 60 min, after which there was only a slight increase in incorporation. Intracellular protein synthesis, in contrast, was linear for periods up to 2 h. Analysis of isolated membranes by polyacrylamide gel electrophoresis in sodium dodecyl sulphate showed that peripheral blood reticulocytes synthesized two proteins in the 4.5 region (MW = 50–60 000 D) and a third protein coinciding with band 6 (glycer‐aldehyde‐3‐phosphate dehydrogenase). Separation of reticulocytes into different age groups on stractan II gradients showed more immature reticulocytes synthesize a wider range of membrane proteins, extending from bands 4.1 to 8. When nucleated red cells were present in the incubations, synthesis of band 3 was also observed. Earlier erythroid precursor present in erythropoietic BFU‐E cultures synthesized spectrin in addition to the other membrane proteins. The data indicate that human red cell membrane protein synthesis follows a programmed pattern and that as the erythroid elements mature they lose the capacity to synthesize certain membrane proteins.