Podocyte Protein, Nephrin, Is a Substrate of Protein Tyrosine Phosphatase 1B

Figure 1

Nck-binding pY residues in human, mouse, and rat nephrin; validation of the phospho-specific antibodies with rat nephrin. In the cytoplasmic domain of rat nephrin, two tyrosine residues, Y1204 and Y1228, are responsible for Nck binding when phosphorylated [5]. The third Nck binding site (Y1176 in human and Y1191 in mouse) [2, 6] is absent in rat. Phospho-specific antibodies developed against the three Nck-binding sites in human [7] were tested against rat nephrin using Cos-1 cells transiently transfected with wild-type or mutant rat nephrin and fyn. pY1204r was recognized by both pY1176h and pY1193h antibodies, while pY1228r was recognized by only pY1217h antibody. Y2F: Y1204/1228F. Nephrin runs as a doublet (180/170 kDa) and p-nephrin corresponds to the upper band [3].