Peroxisome proliferator-activated receptor gamma phosphorylated at serine 273 by cyclin-dependent kinase 5 (PPARγ pSer273 (CDK5-mediated), or PPARγ S273ph (CDK5))

Cyclin-dependent kinase 5-mediated phosphorylation of peroxisome proliferator–activated receptor gamma at serine 273 (S273, or S245 in PPARγ1) is a post-translational modification wherein CDK5, activated by inflammatory and metabolic signals, phosphorylates the nuclear receptor PPARγ at this specific serine residue[5][7]. This modification alters the receptor's pattern of coregulator interactions and target gene expression, uncoupling insulin sensitization from classical adipogenesis and leading to selective insulin resistance without disrupting all PPARγ functions[1][2][4][5][6][7]. Inhibition of this phosphorylation, distinct from traditional agonist activity, improves insulin sensitivity with reduced side effects, making this modified receptor state a promising therapeutic target for type 2 diabetes and metabolic syndrome[5][6][7]. Drugs that inhibit CDK5-mediated phosphorylation (such as some TZDs, SR1664, or UHC1) act to restore a healthier metabolic profile in patients with obesity or diabetes, without the adverse effects associated with full receptor activation[6][7].

Other names

PPARγ S273 phosphorylationPPARγ Ser273 phosphorylationCDK5-mediated PPARγ phosphorylationPPARγ S245 phosphorylation (isoform 1 numbering)PPARγ-pS273

Drugs that **block CDK5-mediated phosphorylation of PPARγ at Ser273** can *improve insulin sensitivity* without full receptor agonism (hence, potentially with fewer side effects than full agonists). - Inhibitors can act allosterically or by altering the conformation of the ligand-binding domain, indirectly preventing access of CDK5 to the S273 residue. - These mechanisms are distinct from classical agonist-induced activation of PPARγ target gene transcription.