Fig. 6. Vari interacts with Nrx through the PDZ domain. (A) A purified C-terminal fragment of Nrx is co-precipitated by purified Glutathione S-transferase fused to the short isoform of Vari and the Vari PDZ domain, but not GST or GST fused to the Vari-SH3 domain. (B) GSTVari and GST-VPDZ co-precipitate Nrx but not Crb from 12-18-hour-old embryo lysates, despite the similarity of the Crb and Nrx C-terminal PDZ-binding motifs (ERLI vs EIFI). NaCl concentrations: 150, 350 and 550 mmol/l. GST, Glutathione S-transferase; IB, immunoblot antisera; VPDZ, Vari PDZ domain.