Researcher(s)
- Nitya Singh, Biological Sciences, University of Delaware
Faculty Mentor(s)
- Arit Ghosh, UD Flow Cytometry Core and Delaware Biotechnology Institute, University of Delaware
Abstract
Erythroid differentiation(ED) is a complex cellular process that requires extensive cellular signaling cascades to lead a hematopoietic stem cell toward the erythroid lineage. Proteostasis via the ubiquitin-proteasome system (UPS) is well-known to regulate this process highly, as well as protein trafficking throughout the cell. However, the mechanical details of how various UPS components such as E3 ligases regulate ED is not well elucidated. There is some evidence that the proteasome will regulate heme-regulated kinases in neuronal cells and heme oxygenase-1 (HO-1) in vascular smooth muscle cells via ER-mediated degradation. Additionally, proteasome inhibition and oxidative stress will disrupt cellular homeostasis during heme stress in mouse embryonic fibroblasts (MEFs). In this study, we have investigated the role of proteasome dysfunction in erythroid differentiation by utilizing Melds19 (erythroleukemia cell line) cells which can be differentiated towards early erythroid lineage via the addition of DMSO. Via proteasomal disruption by the addition of drugs such as MG132, Bortezomib, and Carfilzomib we have investigated the role of the proteasome in transferrin receptor (CD71) trafficking during ED. Our results indicate that CD71 surface expression is affected by proteasome disruption with a suboptimal effect on internal levels of CD71. These results were also seen from mouse primary bone marrow cells indicating a role for the proteasome in both early and late ED. For future work, we intend to parse out the UPS components integral to CD71 trafficking via LC/MS as well as look at whole transcriptomic changes at the single-cell level with scRNAseq to discover UPS components and other novel genes affected by proteasomal dysfunction during ED.
Keyword: Proteasome, Heme, CD71, protein trafficking