Figure 6.

Nephrin is phosphorylated on YDxV sites in normal adult kidneys and a decrease is associated with podocyte injury. (A) Adult rat kidney cortex lysates were immunoprecipitated (IP) with each phospho-nephrin antibody or pan-nephrin, and separated proteins were immunoblotted (IB) with nephrin antibodies. Endogenous nephrin appears as a doublet of 180 and 170 kD, and each of the phospho-nephrin antibodies detected the 180-kD tyrosine-phosphorylated upper species. (B) Glomerular lysates from rats with PAN nephrosis at various time-points or untreated control rats were immunoblotted with phospho-nephrin or nephrin antibodies. We utilized the pY1217 antibody as it displays superior sensitivity. Equivalent amounts of lysate are indicated by tubulin. Data shown are representative of four independent experiments. (C) Densitometric quantitation of phosphorylated nephrin normalized to total nephrin (p-nephrin/nephrin) indicates a decrease in nephrin phosphorylation on the YDQV site upon podocyte injury. *P < 0.05 versus control, n = 4.