Fig. 5: UBA1/E2combo RNAi improves peroxisomal protein import in a PEX-dependent manner.
From: An adaptive stress response that confers cellular resilience to decreased ubiquitination
a HEK293T cells transfected with GFP-PTS1 (green) and immunostained for PMP70 (red) are segmented via machine-learning approaches to identify functional peroxisomes (GFP-PTS1+ and PMP70 + ; yellow) and ghost peroxisomes with defective PTS1-guided protein import (GFP-PTS1- and PMP70 + ; red). b RNAi for UBA1 (yellow) and for E2combo (orange) leads to a significant increase in the number of functional peroxisomes (PMP70 puncta with GFP-PTS1), compared to control cells treated with NT siRNAs (gray). c, d Knockdown of PEX proteins that are upregulated by UBA1/E2combo RNAi rescues back peroxisomal protein import to levels closer to those found in control cells. Similar results are found with the concomitant RNAi of several PEX proteins (PEXcombo; c) and with RNAi for individual PEX proteins (d). In (b–d), n(peroxisomes)>5 × 103 (b), n > 1.9 × 104 (c), and n > 2.6 × 103 (d) with mean ±SEM indicated (the n for each condition are reported in the figure). The statistical significance was calculated by one-way ANOVA, and the significance values (***P < 0.001, &&&P < 0.001, and ns=not significant) are reported in black fonts (for comparisons to siNT+siNT), purple fonts (for comparisons to siUBA1+siNT), and blue fonts (for comparisons to siE2combo+siNT). Source data are provided in the Source data file.
