Fig. 5.

Immunoproteasomal subunits LMP2 (β1i) and LMP7 are poorly expressed in K562 cells in comparison with CD40B cells and dendritic cells. a Total RNA derived from different APCs were used in quantitative real-time RT–PCR to measure relative expression of the proteasomal subunits LMP10 (left), LMP2 (center), and LMP7 (right). All RNA expression levels are normalized to K562. Only mature dendritic cells and K562 cells treated with interferon-γ showed upregulation of LMP10. The immunoproteasomal subunits LMP2 and LMP7 are strongly expressed in both dendritic cells (DC) and CD40B cells relative to K562, which can upregulate both subunits after treatment with interferon-γ. LCL, EBV-transformed lymphoblastoid cell line; iDC, immature dendritic cells; mDC, mature dendritic cells. Standard error <0.09. b Immunoblot of DC, CD40B cells, and K562 cells, showing the expression of the constitutive proteasome subunits (β1, β2, and β5) in all cells and poor expression of the immunoproteasomal components (β1i, β2i, and β5i) in K562 cells. c Rapid induction of the immunoproteasomal components (β1i, β2i) and later induction of β5i in K562 cells after 1–5 days (D1–D5) of treatment with interferon-γ