protein tyrosine phosphatase 1B controlled study 12 human 12 Erythropoietin 10 Phosphorylation 10 erythropoietin 10 human cell 10 protein expression 10 Cell Line 8 Humans 8 Protein Tyrosine Phosphatase, Non-Receptor Type 1 8 article 8 priority journal 8 protein function 8 protein phosphorylation 8 Cell Proliferation 6 Janus Kinase 2 6 Janus kinase 2 6 calcium 6 cell proliferation 6 enzyme activity 6 metabolism 6 signal transduction 6 1-Phosphatidylinositol 3-Kinase 4 4 nitrophenylphosphatase 4 Article 4 Calcium 4 Carbamylated erythropoietin 4 Cell Survival 4 Down-Regulation 4