Fig. 1: Glomerular cell-specific distribution of proteasomal and lysosomal proteins in human and murine glomeruli.
From: The proteasome modulates endocytosis specifically in glomerular cells to promote kidney filtration
A Schematic depiction of the ubiquitin proteasome system (UPS) and autophagosome-lysosome pathway (ALP) with individual marker proteins used for the expression analyses within glomerular cell types. Ubiquitin = polypeptide involved in dynamic regulation of protein function, localization, and stability; Rpt5 = proteasome regulatory subunit 6A (Psmc3) of the proteasome 19S regulatory particle; β5c (Psmb5) = main proteolytic subunit of the constitutive 20S core particle; LC3 = microtubule-associated protein 1A/1B-light chain 3; Lamp1 and Lamp2 = lysosomal-associated membrane proteins 1 or 2; Limp2 (Scarb2) = lysosomal integral membrane protein 2. Distribution of marker proteins (green) by high-resolution confocal images in a healthy human (B) and murine (C) glomerulus in relation to the slit diaphragm protein nephrin (red) and DNA (blue); pc podocyte, mc mesangial cell, ec glomerular endothelial cell, pec parietal epithelial cell, white arrows point toward endothelial lining filled with Lamp2-positive lysosomes, n = 3 individuals. D–F Podocytes (PC), mesangial cells (MC) and glomerular endothelial cells (EC) were bulk-isolated from glomeruli. D Proteomic analyses depict molecular properties of glomerular cell types as shown by the radar plot, whereby two-fold changes of distinct uniprot key words are plotted. Protein values were obtained by label-free quantification results using the MaxQuantLFQ algorithm72. E Relative transcript levels quantified via qRT-PCR of Psmb5 (encoding for β5c) and Scarb2 (encoding for Limp2) normalized to 18S as home keeper in relation to total glomerular transcript levels (dashed line), mean ± SEM, *p = 0.0292 (PC Psmb5), *p = 0.048 (MC Scarb2), one-way ANOVA with Bonferroni post-test for multiple comparisons, n = 12 of 2 pooled independent experiments. F Protein abundance from isolated glomerular cell types determined by immunoblot, equal loading was ensured by loading equal numbers of FACS-sorted PCs, MCs, and ECs, n = 3 independent experiments. Scheme was created with BioRender.com. Source data are provided as a Source Data file.
