Retinoic acid receptor alpha (RARA) (RARA)

The Retinoic acid receptor alpha (RARA) is a nuclear receptor and transcription factor that plays a critical role in regulating myeloid differentiation and cell cycle progression [1, 5]. In Acute Promyelocytic Leukemia (APL), a chromosomal translocation t(15;17) creates the PML-RARA fusion protein, which acts as a dominant-negative repressor of RARA target genes [7, 10]. This fusion protein effectively blocks cell differentiation at the promyelocytic stage and promotes leukemic cell survival by recruiting corepressors that prevent the transcription of maturation-related genes [2, 4]. Therapeutic intervention with all-trans retinoic acid (ATRA) targets the RARA portion of the fusion protein, triggering a conformational switch from transcriptional repression to activation, which restores the differentiation pathway [6, 8]. Arsenic trioxide (ATO) complements this by binding the PML moiety and inducing the degradation of the entire fusion protein through the ubiquitin-proteasome pathway [1, 10]. Together, these agents overcome the differentiation block and induce cell cycle arrest and apoptosis in APL cells, representing a landmark success in molecularly targeted differentiation therapy [2, 10].

Other names

PML-RARA fusion proteinRAR-alphaNR1B1Nuclear receptor subfamily 1 group B member 1t(15;17) fusion protein

All-trans retinoic acid (ATRA) binds to the RARA moiety of the PML-RARA fusion protein, inducing a conformational change that releases corepressors and recruits coactivators, thereby restoring the transcription of genes required for myeloid differentiation [2, 5, 6]. Arsenic trioxide (ATO) binds to the PML moiety of the fusion protein, promoting its degradation via the ubiquitin-proteasome pathway, which relieves the differentiation block and induces apoptosis [1, 10].