Constitutive Androstane Receptor (组成型雄甾烷受体)

Constitutive Androstane Receptor (CAR) is a nuclear receptor. The upstream targets of CAR include protein phosphatase 2A (PP2A), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), epidermal growth factor receptor (EGFR), and various transcription factors such as hepatocyte nuclear factor 4α (HNF4α). PP2A participates in the dephosphorylation of CAR and promotes its nuclear translocation; ERK and MAPK regulate the activity of CAR by affecting its phosphorylation state; EGFR can indirectly regulate the activation of CAR; and transcription factors regulate the expression level of CAR. The downstream hot targets of CAR include many drug metabolizing enzymes and transporter genes, such as CYP2B6 and CYP3A4 in the cytochrome P450 enzyme system (CYP), as well as energy metabolism-related genes such as lipogenesis genes and gluconeogenesis-related genes. CAR activation can improve insulin sensitivity and alleviate the symptoms of obesity and type 2 diabetes; however, its abnormal activation may also be associated with the occurrence and development of liver tumors. CAR plays a key role in drug metabolism, energy metabolism, obesity, type 2 diabetes, and cancer development^{[1][2][3][4][5][6]}.