EPLINα/β interacts with LUZP1. (A) LUZP1 BioID interactors identified in cycling and serum-starved HEK293 cells. BFDR, Bayesian false discovery rate. (B) Schematic representation of human EPLIN isoforms α (600 aa) and β (760 aa), both of which contain a LIM domain. (C) EPLIN isoforms are expressed differently in distinct cell lines. Western blot (WB) analysis of EPLIN expression in human RPE-1, HeLa, U2OS, and MCF-7 cells. (D) GFP-LUZP1 pulls down endogenous EPLIN. coIP experiments using protein extracts prepared from RPE-1 cells stably expressing GFP-centrin (control) or GFP-LUZP1. The fusion proteins were immunoprecipitated using GFP antibody–conjugated beads. GFP and EPLIN antibodies were used to detect the GFP fusions and endogenous EPLIN isoforms, respectively. Asterisk indicates the GFP-LUZP1 band. (E) Both EPLIN isoforms pull-down endogenous LUZP1. coIP experiments using protein extracts prepared from RPE-1 cells stably expressing GFP-centrin (control) or GFP-EPLINα/β. The fusion proteins were immunoprecipitated using GFP antibody-conjugated beads. GFP and LUZP1 antibodies were used to detect the GFP fusions and endogenous LUZP1, respectively. (F) EPLIN localizes to actin structures in RPE-1 cells. RPE-1 cells were stained with antibodies against EPLIN and LUZP1 (top panel). RPE-1 cells stably expressing GFP-EPLINα or β cells and mCherry-LUZP1 (middle and bottom panels) were stained with fluorophore-conjugated phalloidin.(G) EPLIN does not localize to the centrosome or the basal body. RPE-1 cells were stained for EPLIN and PCNT (centrosome marker; top panel). RPE-1 cells stably expressing ARL13B-GFP were stained for GFP and EPLIN.