PPAR

PPAR or Peroxisome proliferator-activated receptors are a group of nuclear receptor proteins that function as transcription factors regulating the expression of genes. They play essential roles in the regulation of cellular differentiation, development, and metabolism (carbohydrate, lipid, protein), and tumorigenesis of higher organisms.

Function

PPARs are members of the nuclear receptor superfamily of ligand-activated transcription factors that regulate gene expression. They are involved in many physiological processes, including lipid metabolism, insulin sensitivity, inflammation, and cell proliferation and differentiation. There are three known isoforms of PPARs: PPARα, PPARβ/δ, and PPARγ, each with distinct roles and tissue distribution.

Structure

PPARs are composed of several domains, including a DNA-binding domain (DBD) and a ligand-binding domain (LBD). The DBD is highly conserved among different PPAR isoforms and other nuclear receptors, while the LBD is more variable, allowing for ligand specificity.

Isoforms

There are three known isoforms of PPARs: PPARα, PPARβ/δ, and PPARγ.

PPARα

PPARα is expressed mainly in liver, kidney, heart, and muscle where it regulates lipid metabolism. It is activated by fatty acids and their derivatives and by fibrate drugs.

PPARβ/δ

PPARβ/δ is expressed ubiquitously and involved in fatty acid oxidation, keratinocyte differentiation, wound healing, and angiogenesis.

PPARγ

PPARγ is expressed predominantly in adipose tissue and the immune system and plays a key role in adipogenesis and immune response. It is the target of thiazolidinedione drugs, which are used to treat type 2 diabetes.

Clinical significance

PPARs have been implicated in numerous diseases, including obesity, diabetes, atherosclerosis, and cancer. Drugs that target PPARs, such as fibrates and thiazolidinediones, are currently used to treat hyperlipidemia and diabetes, respectively.

See also

• Nuclear receptor
• Transcription factor
• Gene expression
• Lipid metabolism
• Insulin sensitivity
• Inflammation
• Cell proliferation
• Cell differentiation
• Obesity
• Diabetes
• Atherosclerosis
• Cancer

PPAR Resources
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