Effective anti-diabetic drugs known as thiazolidinediones (e.g. rosiglitazone, pioglitazone) exert their therapeutic effects through their agonistic activity at the peroxisome proliferator-activated receptor gamma (PPAR gamma). As a multidomain transcription factor, PPAR gamma forms heterodimers with different retinoid X receptors (RXRs) to modulate target gene expression at the transcriptional level in response to natural or synthetic ligands. Difficulties in producing either of the two major human PPAR gamma isoforms (PPAR gamma 1 and PPAR gamma 2) as pure full-length proteins in adequate quantity has hindered detailed mechanistic studies of PPAR gamma and its ancillary protein partners. Here we report an efficient transient expression system to produce recombinant human full-length PPAR gamma 2 protein. The DNA encoding the human full-length PPAR gamma 2 was cloned into a mammalian episomal vector and transiently expressed in human embryonic kidney 293 (HEK293-6E) cells with an expression level of 10 mg/L culture. Identity of the purified recombinant PPAR gamma 2 protein was confirmed by mass spectrometry analysis. The purified PPAR gamma 2 protein was active in ligand binding and could be phosphorylated in vitro by Cdk5/p25 at Ser 273. Further studies showed that selected PPAR gamma modulators inhibited Cdk5-mediated PPAR gamma 2 Ser 273 phosphorylation in vitro. Our results demonstrate the feasibility of producing large quantities of pure and functional human full-length PPAR gamma 2 suitable for drug discovery applications. (C) 2013 Elsevier Inc. All rights reserved.