Fig. 4: PUX3, PUX4, and PUX5 negatively regulate the degradation of SUN1. | Nature Communications

Fig. 4: PUX3, PUX4, and PUX5 negatively regulate the degradation of SUN1.

From: Proximity labeling proteomics reveals critical regulators for inner nuclear membrane protein degradation in plants

Fig. 4

a The pux3, pux4, and pux5 mutations generated by CRISPR/Cas9 in the 35S: HA-BioID2-SUN1 background. b In vivo degradation assay for HA-BioID2-SUN1 in WT and the pux3 pux4 pux5 triple mutant background. c Time-course densitometric analysis of the HA-BioID2-SUN1 protein level in the presence of CHX using actin as the control. Error bars represent SD from two independent biological replicates. d Peptide intensity values of nucleoskeleton proteins measured by PL-FLQMS using 35S: HA-BioID2-SUN1 plants in WT and pux3 pux4 pux5 background. Error bars represent SD from two independent biological replicates. e Models for the function of PUX3/4/5 in plant INM protein degradation. INM proteins are ubiquitinated by unknown E3 ubiquitin ligases and subsequently recruit the CDC48 complex for proteasome degradation (left). PUX3/4/5 play a negative role in regulating the INM protein degradation in plants. One hypothesis is that PUX3/4/5 may protect INM proteins from non-specific degradation by directly interfering with the ATPase activity of CDC48 at the INM (middle). Alternatively, PUX3/4/5 may recruit the CDC48 complex to the INM to degrade the INM-localized E3 ligases that initiate INM protein degradation in plants (right). PUX3/4/5 are anchored to the INM through interacting with the nucleoskeleton.

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