What causes a precursor cell [1] to divide into identical copies or become specialized? The balance between cell division and differentiation is finely regulated. In the case of producing adipose tissue (adipogenesis), biology researchers at the CEA's Institut François-Jacob suggest that the interaction between two proteins, FOG-2 and pRb, controls the choice of adipose tissue specialization: white fat for lipid storage, or brown fat for the body's thermogenesis.

The scientists concentrated on FOG-2, known to have a role in adipogenesis. They identified a peptide motif (LXCXE) in FOG-2 that gives it the ability to interact with pRb, a protein that halts the progression of the cell cycle. The researchers developed a rodent model in which the LXCXE motif was removed from FOG-2. Animals expressing the mutated form of FOG-2 are hyperactive, and their resistance to cold and obesity is enhanced. In addition, their white fat is partly converted into brown fat.

This study suggests new avenues for the prevention of adipose tissue pathologies, such as obesity.