FIG. 9.

Schematic representation of the mechanistic model of activation of RARα-mediated transcription by the core. (i) In the absence of the core, Sp110b is located in the nucleus, playing a suppressive role in RARα-mediated transcription. (ii) In the presence of the core, Sp110b is sequestered to ER membranes through interaction with the core, which is located on the cytoplasmic surfaces of ER membranes. This sequestration results in a reduction of the transcriptional suppressive effect of Sp110b in the nucleus. Consequently, ATRA-induced transcription and expression of RARα-responsive genes, such as tTGase, are enhanced.