Objective:

To investigate whether prohibitin (PHB) is a target gene in adipocyte differentiation and modulates insulin-induced adipocyte differentiation.

Design:

3T3-L1 preadipocyte overexpressing wild-type PHB and PHB mutant (lacking tyrosine-114 phosphorylation site) with or without insulin.

Results:

The treatment of 3T3-L1 fibroblasts with insulin or peroxisome proliferator-activated receptor-γ agonist resulted in an upregulation of PHB in a dose-and time-dependent manner. An analysis of the PHB promoter sequence revealed the presence of putative insulin-response elements and CCAAT/enhancer-binding protein transcription elements within∼ 1 kb upstream of the translation initiation site. The functional relevance of these sites was determined using reporter gene assay. Surprisingly, PHB was also found to be regulated by leptin. Furthermore, the overexpression of PHB in 3T3-L1 fibroblasts was sufficient to induce adipogenesis.

Conclusion:

In summary, we have identified PHB as an important protein in adipocyte differentiation.

Introduction

Obesity is a growing concern worldwide. It is a risk factor in a number of chronic diseases that afflicts our society, including type 2 diabetes, cardiovascular disease and cancer. 1 In recent years, numerous studies have focused on identifying the mechanism of the development of obesity, which is a process of increasing the number of adipocytes (hyperplasia), the enrichment of adipocytes with each carrying greater amount of fat (hypertrophy) or both. 1, 2 The ability to regulate the number of adipocytes and/or size of adipocytes is a key in the prevention and treatment of obesity and also in the origin of chronic diseases.