The role of a JNK‐scaffolding protein in endodermal differentiation

Abstract

Retinoic acid (RA) is a morphogen that induces endodermal differentiation of P19 murine embryonic carcinoma cells. RA-induced differentiation of P19 cells has been shown to critically require Gα13 - the α-subunit of the heterotrimeric G protein G13 – and its activation of JNK-module. However, the mechanism through which Gα13 is linked to JNK-module is unknown. Here, we report that RA stimulates the expression of JNK-interacting leucine zipper protein (JLP), a newly identified JNK-scaffolding protein, in addition to Gα13 in P19 cells. A physical interaction between JLP and Gα13 can also be seen in RA-stimulated P19 cells. Similar to the effects seen with the silencing of Gα13 and the inhibition of JNK, silencing JLP also abrogates RA-mediated differentiation. Therefore our studies presented here identify a novel role for JLP in RA-mediated endodermal differentiation, providing a new signaling conduit to transmit signals from RA-Gα13 to JNK module (Supported by GM 49897).