| COPR 1 and its longer variant COPR 2 target the AF 2 domains of NR but exhibit quantitative differences in their functional interactions with RAR , RXRalpha and PPAR . ^^^ COPR 1 and its longer variant COPR 2 target the AF 2 domains of NR but exhibit quantitative differences in their functional interactions with RAR , RXRalpha and PPAR . ^^^ |