Expression patterns of DEPDC1B in normal tissues and tumor cells and effects of DEPDC1B on Rho GTPase expression and the subcellular localization of Rac1. (A) Expression of DEPDC1B mRNA as presented by northern blot analysis of various human tissues, by using DEPDC1B cDNA as a probe. A human multiple tissue northern blot containing poly (A)+ RNA was probed with full-length DEPDC1B DNA. (B) FLAG epitope-tagged forms of DEPDC1B were transiently expressed in 293 T cells, and FLAG-DEPDC1B proteins were detected by using antiFLAG antibodies with a molecular weight of approximately 58 kDa. (C) DEPDC1B protein was abundantly expressed in oral cancer tissue (T) compared with cognate normal tissue (N). (D) Rho, and Rac1 were detected by western blotting of cell lysates from Rat6 cells stably expressing DEPDC1B. (E) 3X FLAG epitope-tagged forms of DEPDC1B were transiently expressed in 293 T. Anti-FLAG antibodies were used for immunoprecipitation. Anti-Rho, −CDC42, and -Rac1 antibodies were used for western blotting. (F) Membrane (Mem.) and cytosolic (Cyto.) fractions from Rat6 or Hep3B/T2 control (C) and DEPDC1B-expressing cells were analyzed using immunoblotting for Rac1 and RhoGDIβ. (G) GTP loading in Rac1 was determined and a PAK PBD binding assay was used to analyze in Rat6 or Hep3B/T2 cells that stably expressed DEPDC1B.