Fig. S3.

Phosphomimetic mutation at S1674 in GIV promotes cyst formation in MDCK cells. (A) GIV expression in type II MDCK cell lines expressing WT, 74D, and 74A constructs. Equal aliquots of whole-cell lysates of parental (vector alone; Vec), GIV-WT, GIV-74D, and GIV-74A MDCK cell lines were analyzed for GIV and tubulin by immunoblotting (IB). (B) MDCK cells in A were seeded in collagen gels and monitored for cyst formation by phase contrast microscopy. Representative images are shown for each cell line. MDCK parental cells and those expressing GIV-WT and GIV-74D, but not those expressing GIV-74A mutant, form cysts with a distinct central lumen (L).