Fig. 2.

Gα₁₃ predominantly mediates RhoA activation downstream of GRPR in Caco-2 cells. (A, B) Caco-2 cells transfected with scrambled or Gα₁₃-SMARTpool siRNA for 48 hours to obtain Gα₁₃-specific knockdown without affecting Gα₁₂ expression. (+) Gα_12/13 lanes contain purified recombinant Gα₁₂ or Gα₁₃ subunits used as positive control. (C) Caco-2 cells were serum-starved overnight and then stimulated with GRP for 10 minutes and subsequently used for GST-RBD pulldown (see Materials and Methods). Precipitate and lysate samples were then immunoblotted to detect RhoA, Gα₁₃, and GAPDH. GAPDH was used as loading control. (D) Statistical densitometric analysis of n = 4. Shown are mean values ± S.E.M.; ***P < 0.001. RBD, Rho binding domain.