RNF5 in ER-Related Disorders Figure 1. Alteration of RNF5 pattern is evident in muscle biopsies from both patients with sIBM and in a hIBM mouse model. A. Immunohistological analysis of RNF5 protein in a normal muscle biopsy and in biopsies from 2 representative sIBM patients. RNF5 staining was also positive in aggregates from 10 independent sIBM patients (not shown). B. Muscle cross-sections from 3 sIBM patients immunostained with RNF5 antibody exhibiting high levels of RNF5 protein in giant aggregates. C. Co-localization of RNF5 with beta-amyloid protein (6E10) inclusions in a representative muscle cross-section from a sIBM patient. D. Co-staining of muscle sections from 2 sIBM patients with RNF5 and SMI31, a marker for phospho-tau protein. Arrows point to phospho-tau containing aggregates and arrowheads to RNF5 staining. E. Elevated RNF5 protein levels in biopsies from 3 IBM patients. RNF5 was immunoprecipitated from equal protein amounts prepared from biopsies of sIBM patients using RNF5 polyclonal antibody. The resulting immunoprecipitates were analyzed by western blot using RNF5 antibody. Equal volumes of supernatants from the respective immunoprecipitations were analyzed for GAPDH expression, confirming that the immunoprecipitation reactions were performed using comparable amounts of extracts. F. Immunohistological analysis of RNF5 protein in control (a) and DMRV mutant mice (b–d). c and d represent higher magnification and highlight the presence of dense intrafiber staining for RNF5 in muscle fibers (arrows on panel c point to RNF5 staining within rimmed vacuoles [24] whereas arrow on panel d points to RNF5 staining within centrally located nuclei). doi:10.1371/journal.pone.0001609.g001 PLoS ONE | www.plosone.org 3 February 2008 | Volume 3 | Issue 2 | e1609