Hyperglycosylation of eosinophil ribonucleases in a promyelocytic leukemia cell line and in differentiated peripheral blood progenitor cells.
We evaluated two independent models of eosinophil differentiation for their ability to synthesize the ribonuclease toxins eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP). Cells from the clone 15 subline of HL-60 (human promyelocytic leukemia) produced both EDN and ECP; production of EDN increased in response to butyric acid (BA). CD34+ peripheral blood progenitor cells (PBPCs) grown with cytokines promoting eosinophil differentiation also produced EDN. EDN from both the clone 15 and PBPCs was more heterogeneous and heavily glycosylated (approximately 22-45 kDa) than EDN from the mature peripheral blood eosinophils (18-25 kDa). The heterogeneity of EDN from the clone 15 cells was not altered by endoglycosidase Hf, whereas treatment with peptide-N-glycosidase F (PNGase F) produced a single-band immunoreactive band (approximately 15 kDa). In contrast, only the highest molecular weight forms of EDN from differentiated PBPCs were eliminated by PNTGase F (reduced to 22-35 kDa), suggesting the presence of uncharacteristic forms of posttranslational modification. Synthesis of hyperglycosylated proteins has not been previously reported in PBPCs and is a feature shared with tumor cells and cell lines.
Tiffany
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HL
Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Li
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Rosenberg
H F
HF
D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D047208:Eosinophil-Derived Neurotoxin; D004804:Eosinophils / Q000166:cytology / Q000201:enzymology*; D006031:Glycosylation; D006412:Hematopoietic Stem Cells / Q000201:enzymology*; D006801:Humans; D066298:In Vitro Techniques; D007951:Leukemia, Myeloid / Q000201:enzymology; D009498:Neurotoxins / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012260:Ribonucleases / Q000378:metabolism*
D002087:Butyrates; D009498:Neurotoxins; D020148:Butyric Acid; D047208:Eosinophil-Derived Neurotoxin; D012260:Ribonucleases