WTIP links nephrin to Lats1 inhibition.
A, lysates from HEK293T cells coexpressing CD16/7-nephrinY3F or CD16/7-nephrinY3F-3xSH3 with Lats1-FLAG in the presence or absence of WTIP-HA were stimulated with anti-CD16 antibody, immunoprecipitated (IP) for GFP, and immunoblotted (IB) for GFP, FLAG, and HA. Lats1 binds the CD16/7-nephrinY3F-3xSH3 fusion protein but not CD16/7-nephrinY3F alone upon coexpression of WTIP. B, immunoblot of equivalent lysates from the third and fourth lanes of A with phospho-Lats1 Ser-909 shows a decrease in Lats1 activation upon complex formation between CD16/7-nephrinY3F-3xSH3, WTIP, and Lats1. C, densitometry of B, showing a statistically significant 2.4-fold reduction of Lats1 phosphorylation on Ser-909 coincident with complex formation between CD16/7-nephrinY3F-3xSH3, WTIP, and Lats1 (n = 4). **, p < 0.01.