RGS2 promotes adipocyte differentiation in the presence of ligand for peroxisome proliferator-activated receptor gamma.

The events at the earliest stage of adipocyte differentiation are yet to be fully elucidated. Previously, we cloned the genes that are induced at the beginning of the differentiation of mouse 3T3-L1 preadipocyte cells. We found that the gene expression of regulators of G protein signaling-2 (RGS2) rapidly increased after the addition of inducers and decreased at 3-12 h. The expression pattern of RGS2 mRNAs differed among growth-arrested and proliferating 3T3-L1 cells and NIH-3T3 cells, indicating a specificity for adipogenesis. Here we report that the ectopic expression of RGS2 using a retroviral system in mouse NIH-3T3 cells promotes adipogenesis only in the presence of BRL49653, which is a ligand for the peroxisome proliferator-activated receptor gamma (PPARgamma). These results strongly suggest that RGS2 play a crucial role in the program of adipocyte differentiation and may contribute to the function of PPARgamma.