F9 embryonic carcinoma (EC) cells undergo extra-embryonic endodermal (ExE) differentiation in response to retinoic acid (RA) treatment, which induces the expression of two isoforms (p96 and p67) of the adaptor protein, Disabled-2 (Dab2). In the current study, constitutive and ectopic expression of the p96 isoform induced ExE differentiation in F9 EC cells in the absence of RA treatment via the activation of GATA-4 by p96. During the RA-induced differentiation process, Dab2 expression is induced by the GATA factors in a coherent feed-forward loop; on the other hand, we showed that p96 regulates GATA-4 in a positive feed-back manner in this study. Our results indicate that p96 Dab2 plays a key role in the ExE differentiation process. (C) 2012 Elsevier Inc. All rights reserved.