RESUMO
We previously reported that three point mutations in SASH1 and mutated SASH1 promote melanocyte migration in dyschromatosis universalis hereditaria (DUH) and a novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype. However, the underlying mechanism of molecular regulation to cause this hyperpigmentation disorder still remains unclear. In this study, we aimed to investigate the molecular mechanism undergirding hyperpigmentation in the dyschromatosis disorder. Our results revealed that SASH1 binds with MAP2K2 and is induced by p53-POMC-MC1R signal cascade to enhance the phosphorylation level of ERK1/2 and CREB. Moreover, increase in phosphorylated ERK1/2 and CREB levels and melanogenesis-specific molecules is induced by mutated SASH1 alleles. Together, our results suggest that a novel SASH1/MAP2K2 crosstalk connects ERK1/2/CREB cascade with p53-POMC-MC1R cascade to cause hyperpigmentation phenotype of DUH.
Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Hiperpigmentação/metabolismo , MAP Quinase Quinase 2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Linhagem Celular Tumoral , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , MAP Quinases Reguladas por Sinal Extracelular/genética , Células HEK293 , Humanos , Hiperpigmentação/genética , MAP Quinase Quinase 2/genética , Modelos Biológicos , Mutação , Transtornos da Pigmentação/congênito , Transtornos da Pigmentação/genética , Transtornos da Pigmentação/metabolismo , Ligação Proteica , Interferência de RNA , Transdução de Sinais/genética , Dermatopatias Genéticas/genética , Dermatopatias Genéticas/metabolismo , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
p53-Transcriptional-regulated proteins interact with a large number of other signal transduction pathways in the cell, and a number of positive and negative autoregulatory feedback loops act upon the p53 response. P53 directly controls the POMC/α-MSH productions induced by ultraviolet (UV) and is associated with UV-independent pathological pigmentation. When identifying the causative gene of dyschromatosis universalis hereditaria (DUH), we found three mutations encoding amino acid substitutions in the gene SAM and SH3 domain containing 1 (SASH1), and SASH1 was associated with guanine nucleotide-binding protein subunit-alpha isoforms short (Gαs). However, the pathological gene and pathological mechanism of DUH remain unknown for about 90 years. We demonstrate that SASH1 is physiologically induced by p53 upon UV stimulation and SASH and p53 is reciprocally induced at physiological and pathophysiological conditions. SASH1 is regulated by a novel p53/POMC/α-MSH/Gαs/SASH1 cascade to mediate melanogenesis. A novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype. Our study demonstrates that a novel p53/POMC/Gαs/SASH1 autoregulatory positive feedback loop is regulated by SASH1 mutations to induce pathological hyperpigmentation phenotype.