A Compendium of Urinary Biomarkers Indicative of Glomerular Podocytopathy

Figure 1

The protein biomarkers discussed in the paper are highlighted in this figure to show their cellular localization and the protein-protein associations that occur in glomerular podocyte foot processes. The podocyte is situated upon the glomerular basement membrane (GBM) and is anchored to it in part by alpha 3 integrins (Intα3). The slit diaphragm is illustrated with nephrin from adjacent foot processes interacting and forming a “zipper-like” structure. One can appreciate how the actin cytoskeleton (composed of F-actin) brings together the apical, lateral, and basal surfaces of the foot process: membrane proteins (podocalyxin, nephrin, alpha 3 integrin, etc.) via adaptor proteins (CD2AP, α-actinin 4, etc.) interact with actin, and as such they can modulate it. Wilms tumor protein 1 (WT1) has been identified as a transcription factor and is also localized within exosomes. Mindin has been localized within glomeruli, specifically to podocytes, and in cell culture found to be secreted into culture medium. Further details of each protein can be found in their respective sections within the paper.