Ex vivo production of red blood cells (RBCs) represents a promising alternative for transfusion medicine. Several strategies were described to generate erythroid cell lines from different sources, including embryonic, induced pluripotent and hematopoietic stem cells. With imBMEP-A, we have previously generated the first erythroid cell line directly derived from reticulocyte progenitors. However, the translation of cultured RBCs into clinical use is currently impeded by the inability to scale up to clinically meaningful doses primarily due to impaired in vitro enucleation of RBC progenitor cell lines in general. To identify factors contributing to the inefficient enucleation in immortalized RBC progenitor cell lines, we conducted a proteome analysis of the imBMEP cell line in comparison to hematopoietic stem cells (HSCs). For a detailed description of the cell culture condition, please see linked publication.