Emerin and lamin B receptor (LBR) are abundant transmembrane
proteins
of the nuclear envelope that are concentrated at the inner nuclear
membrane (INM). Although both proteins interact with chromatin and
nuclear lamins, they have distinctive biochemical and functional properties.
Here, we have deployed proximity labeling using the engineered biotin
ligase TurboID (TbID) and quantitative proteomics to compare the neighborhoods
of emerin and LBR in cultured mouse embryonic fibroblasts. Our analysis
revealed 232 high confidence proximity partners that interact selectively
with emerin and/or LBR, 49 of which are shared by both. These included
previously characterized NE-concentrated proteins, as well as a host
of additional proteins not previously linked to emerin or LBR functions.
Many of these are TM proteins of the ER, including two E3 ubiquitin
ligases. Supporting these results, we found that 11/12 representative
proximity relationships identified by TbID also were detected at the
NE with the proximity ligation assay. Overall, this work presents
methodology that may be used for large-scale mapping of the landscape
of the INM and reveals a group of new proteins with potential functional
connections to emerin and LBR.
Emerin and LBR are abundant transmembrane proteins of the nuclear envelope (NE) that are concentrated at the inner nuclear membrane (INM). Although both proteins interact with chromatin and nuclear lamins, they have distinctive biochemical and functional properties. Here we have deployed proximity labeling using the engineered biotin ligase TurboID (TbID) and quantitative proteomics to compare the neighborhoods of emerin and LBR in cultured mouse embryonic fibroblasts (MEFs). Our analysis revealed 232 high confidence proximity partners (HCPP) that interact selectively with emerin and/or LBR, 49 of which are shared by both. These included previously characterized NE-concentrated proteins, as well as a host of additional proteins not previously linked to emerin or LBR functions. Many of these are TM proteins of the ER and include two E3 ubiquitin ligases. Using the proximity ligation assay as an orthogonal approach, we validated the interactions described by proximity labeling for 11/12 proteins analyzed, supporting the robustness of our analysis. Overall, this work presents methodology that may be used for large-scale mapping of the landscape of the INM and reveals a group of new proteins with potential functional connections to emerin and LBR.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.