Dynamic migration of CRB2 in developing podocytes.

Double immunofluorescence for CRB2 and synaptopodin followed by confocal microscopy in the newborn mouse kidney. CRB2 was located both in the glomerular visceral (S-shape, white arrow) and parietal (S-shape, arrowhead) immature epithelium, where immunostaining was observed at the apicolateral and apical membranes, respectively. At the early capillary stage, CRB2 was predominantly localized at apical (capillary-1, arrowhead) and apicolateral (capillary-1, white arrow) regions, whereas synaptopodin was found at the basolateral side in premature podocytes (capillary-1, yellow arrow). Plasma membrane localization of CRB2 on parietal epithelium was preserved (capillary-1, arrowhead). In more mature podocytes (capillary-2, capillary-3, and mature), CRB2 had moved down to the basolateral side and eventually colocalized with synaptopodin at the foot processes (CRB2, white arrow; synaptopodin, yellow arrow). Through the capillary stage, CRB2 expression in glomerular parietal cells was positive, though its expression became faint in the mature glomerulus (asterisk in CRB2 lane). An enlarged view is displayed within the rectangle.