FIGURE 4.

RhoGDIβ blunted BMP4-induced adipocyte lineage commitment via inactivation of Rac1. C3H10T1/2 cells plated at low density, treated with or without BMP4 until post-confluence. The amount of Rac1 bound to GST-PAK1-PBD fusion protein was measured by Western blotting as described under “Experimental Procedures” (A). GST-PAK-PBD-bound active Rac1 was detected in C3H10T1/2 cells infected with retrovirus harboring RhoGDIβ or empty vector, cultured with or without BMP4 until post-confluence (B). Active Rac1 was assayed in C3H10T1/2 cells co-overexpressed with RhoGDIβ and RacV12, cultured with or without BMP4 (C). RacV12 rescued the adipocyte lineage commitment blocked by RhoGDIβ as assessed by 422/aP2 (D) and Oil Red O staining (E).