Fig. 5.

HL ERAD occurs via the proteasomal pathway. A: CHO cells expressing HL, PL, or H2b were incubated with or without the proteasomal inhibitors MG132 and MG262. The accumulation of degradation products is clearly seen in H2b (arrowhead), a well-established example of a secretory protein that undergoes proteasome-mediated degradation. Degradation products also appear when HL is treated with either inhibitor, in contrast to PL, showing no detectable degradation via the proteasomal pathway. B: The HL degradation product is unglycosylated. HL from CHO cells incubated with or without the proteasomal inhibitor MG132 was subjected to endo H cleavage. The arrow points to the HL degradation product (two bands).