Fig. 8

RACK1 activation (A) and hypotheses about the possible direct interaction of RACK1 with embryonal marker expression (B). A) According to previous studies, RACK1 can be activated by PKC, which, in turn, is activated by calcium waves induced by PE or a cocktail of FGFs (GFs). BL treatment depletes the calcium wave. B) The translation of the mRNA of GATA4 could involve the IRES sequence because our bioinformatic analysis revealed a long sequence in the 5? UTR. RACK1 interacts with the ITAF/IRES complex to permit ribosome assembly. The acetylation of GATA4 by the transcriptional coactivator p300 induces its multimerization and activates its DNA binding activity. GATA4 permits the transcription of cardiac hypertrophic response genes, including atrial natriuretic factor (ANF), brain natriuretic peptide (BNP), and myosin heavy chain 7 (MYH7). Preliminary bioinformatic analysis revealed that the long 5?UTR of WT1 is compatible with the IRES sequence. RACK1 can interact with the ITAF/IRES complex for ribosome assembly during translation. WT1, as a transcription factor, can induce epicardial cell proliferation and transdifferentiation. NFAT2 can interact with RACK1 in two ways: translation via the eIF-3d 5?UTR and cooperation in transporting the phosphorylated protein to the nucleus. NFAT2 is a powerful transcription factor for the proliferation and transdifferentiation of the endocardium and endothelial cells.