Table 1.
Loss-of-function studies on PPARγ cofactors in adipogenesis and energy metabolism
| PPARγ cofactor | Phenotype in the absence of the cofactor | |
|
| ||
| Cell-based studies | Mouse studies | |
|
| ||
| Brg1, hBrm (SWI/SNF components) | Blocked adipogenesis (Salma et al. [25]) | — |
| Reduced presence of Pol II and GTFs on the promoter (Salma et al. [25]) | ||
| Decreased PPARγ transcription (Salma et al. [25]) | ||
|
| ||
| TIF2 | Increased lipolysis (Picard et al. [50]) | Enhanced adaptive thermogenesis (Picard et al. [50]) |
| Protection against obesity (Picard et al. [50]) | ||
| Increased insulin-sensitivity (Picard et al. [50]) | ||
| Improved metabolic profile. Increased lipolysis (Picard et al. [50]) | ||
| Decreased presence of PPARγ | ||
|
| ||
| SRC-1 | — | Predisposition to obesity (Picard et al. [50]) |
| Reduced energy expenditure (Picard et al. [50]) | ||
| Reduced fatty acid oxidation in brown adipose tissue (Picard et al. [50]) | ||
| Decreased energy expenditure, attenuated fatty acid oxidation (Picard et al. [50]) | ||
|
| ||
| SRC-1/pCIP double knockout | Abrogated preadipocyte differentiation (Wang et al. [51]) | Diminished lipid storage in brown fat; increased caloric intake on both chow and high-fat diet due to increased leptin levels; resistance to diet-induced obesity; increased basal metabolic rate and energy expenditure (Wang et al. [51]) |
| Reduced expression of PPARγ-target genes, including UCP-1, due to corepressor recruitment and decreased PPARγ recognition of PPREs (Wang et al. [51]) | ||
|
| ||
| PGC-1α | Impaired induction of thermogenic genes in BAT (Uldry et al. [52]) | Reduced mitochFondrial function (Lin et al. [53]) |
| Decreased number and impaired function of mitochondria (Uldry et al. [52]) | Resistance to obesity and hyperactivity (Lin et al. [53]) | |
|
| ||
| TRAP220/DRIP205/PBP | Defective PPARγ-stimulated adipogenesis (Ge et al. [31]) | Defective vascular development similar to that seen in PPARγ-null mice (Barak et al. [54]; Zhu et al. [55]) |
|
| ||
| PRIP/NRC/RAP250/TRBP | Decreased PPARγ-mediated transcriptional activation (Antonson et al. [56]; Zhu et al. [57]) | — |
|
| ||
| RIP140 | Upregulation of genes involved in energy dissipation (Poweka et al., 2006) | Increased oxygen consumption and resistance to high-fat diet-induced obesity (Leonardsson et al. [58]) |
| Increased PGC-1α expression (Poweka et al., 2006) | Expression of lipgenic enzymes is decreased. UCP-1 (involved in energy dissipation in BAT) expression is increased (Leonardsson et al. [58]) | |
|
| ||
| NCoR and SMRT | Increased adipocyte differentiation (Yu et al. [42]) | — |
|
| ||
| Sirt1 | Decreased NCoR levels (Picard et al. [43]) | — |