| Cross talk between glucocorticoid and retinoic acid signals involving glucocorticoid receptor interaction with the homoeodomain protein Pbx 1 . ^^^ A physical interaction between the GR and Pbx 1 proteins was demonstrated in vivo by co immunoprecipitation experiments . ^^^ These results are compatible with a model in which the GC / RA synergy is mediated by a direct interaction between the GR and Pbx 1 . ^^^ On the basis of the ubiquitous expression of both GR and Pbx 1 , a number of genes regulated by Pbx are likely to be important targets for GC mediated ' cross talk ' . . ^^^ |