The SHP2-ERK2 signaling pathway regulates branched I antigen formation by controlling the binding of CCAAT/enhancer binding protein α to the IGnTC promoter region during erythroid differentiation.
Phosphorylation status of the transcription factor CCAAT/enhancer binding protein α (C/EBPα) has been demonstrated in a human hematopoietic cell model to regulate the formation of branched I antigen by affecting its binding affinity to the promoter region of the IGnTC gene during erythroid and granulocytic differentiation.



The K-562 cell line was induced to differentiate into red blood cells (RBCs) or granulocytes by sodium butyrate or retinoic acid, respectively, to study the involvement of three MAP kinase pathways in I antigen synthesis. The regulatory effects of the extracellular signal-regulated kinase (ERK)2-Src homology region 2 domain-containing phosphatase 2 (SHP2) pathway on phosphorylation status and binding affinities of C/EBPα as well as the subsequent activation of IGnTC and synthesis of surface I formation were studied in wild-type K-562 cells and in mutant cells that overexpress ERK2 and SHP2.



We found that SHP2-ERK2 signaling regulates the phosphorylation status of C/EBPα to alter its binding affinity onto the IGnTC promoter region, thereby activating the synthesis of cell surface I antigen formation during erythropoiesis.



SHP2-ERK2 signaling acts upstream of C/EBPα as a regulator of cell surface I antigen synthesis. Such regulation is specific for RBC but not for granulocyte differentiation.
School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University.
Yi-Jen
YJ
Liao
Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.|Department of Medical Research, Mackay Memorial Hospital, New Taipei City, Taiwan.
Yen-Hua
YH
Lee
Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
Fu-Ling
FL
Chang
Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
Hsun
H
Ho
Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
Chin-Han
CH
Huang
Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
Yuh-Ching
YC
Twu
D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000378:metabolism*; D004920:Erythropoiesis; D006801:Humans; D007048:I Blood-Group System / Q000096:biosynthesis*; D020014:K562 Cells; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D017349:N-Acetylhexosaminyltransferases; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11 / Q000378:metabolism*; D015398:Signal Transduction
D022763:CCAAT-Enhancer-Binding Protein-alpha; D007048:I Blood-Group System; C106501:N-acetylglucosaminyltransferase IGnT; C000617996:GCNT2 protein, human; D017351:N-Acetylglucosaminyltransferases; D017349:N-Acetylhexosaminyltransferases; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11