Requirement of the SIM for the recruitment of theβ regulatory subunit of the 11S proteasome to PML NBs in response to As₂O₃.

<p>Confocal immunofluorescence analysis of PML and of the β regulatory subunit of the 11S proteasome (11Sβ) were performed on U373MG cells stably expressing PMLIII (A) or PMLIII-SIM (B), treated or not with 5 μM of As₂O₃ for 1 h, 24 h or 48 h. PML and 11Sβ were detected with a mouse anti-PML and a rabbit anti-11Sβ antibodies followed by the corresponding anti-IgG antibody conjugated to Alexa 594 (red) and 488 (green), respectively. The merged images at 1 h of As₂O₃ treatment revealed in all cells a co-localization of endogenous 11Sβ with PMLIII but not with PMLIII-SIM mutant.