The Role of Proteasome in the Cell Cycle Progression of Induced Pluripotent Stem Cells

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Şahin Z. S.

CELLULAR AND MOLECULAR BIOLOGY, no.63, pp.1-4, 2017 (SCI-Expanded)


Most of eukaryotic proteins are degraded by proteasomal system. Conserved activity of proteasome provides degradation of damaged proteins and regulation of signaling pathways. Mesenchymal stem cells (MSCs) are selfrenewing cells with the ability of multipotency and important in stem cell research because of easy isolation and ethical considerations about embryonic stem cells (ESCs). Induced pluripotent stem cells (iPSCs) are also promising in stem cell research, which are conducted via re-programming of somatic cells. Previously, proteasome activity was shown to be high in hESCs and iPSCs. In this study, the relation between proteasome activity and cell cycle stages were compared. First of all, proteasome activity of MSCs, iPSCs, fibroblasts was measured. Then, the cell cycle stages of cells were determined and phosphorylated retinoblastoma levels were analyzed. Proteasome activity of iPSCs was higher than MSCs and fibroblasts. Most of iPSCs were found in S and G2/M while MSCs and fibroblasts were in G0/G1 phase. Our data showed that phospho-pRb levels were about 4 times and 2 times higher in iPCSs and in MSCs compared to fibroblasts. It can be concluded that higher proteasomal activity is related with higher potency of cells and Phospho-pRb is also induced in the same way.