RESUMEN
Collagen posttranslational processing is crucial for its proper assembly and function. Disruption of collagen processing leads to tissue development and structure disorders like osteogenesis imperfecta (OI). OI-related collagen processing machinery includes prolyl 3-hydroxylase 1 (P3H1), peptidyl-prolyl cis-trans isomerase B (PPIB), and cartilage-associated protein (CRTAP), with their structural organization and mechanism unclear. We determine cryo-EM structures of the P3H1/CRTAP/PPIB complex. The active sites of P3H1 and PPIB form a face-to-face bifunctional reaction center, indicating a coupled modification mechanism. The structure of the P3H1/CRTAP/PPIB/collagen peptide complex reveals multiple binding sites, suggesting a substrate interacting zone. Unexpectedly, a dual-ternary complex is observed, and the balance between ternary and dual-ternary states can be altered by mutations in the P3H1/PPIB active site and the addition of PPIB inhibitors. These findings provide insights into the structural basis of collagen processing by P3H1/CRTAP/PPIB and the molecular pathology of collagen-related disorders.
Asunto(s)
Colágeno , Microscopía por Crioelectrón , Ciclofilinas , Proteínas de la Matriz Extracelular , Humanos , Colágeno/metabolismo , Colágeno/química , Proteínas de la Matriz Extracelular/metabolismo , Proteínas de la Matriz Extracelular/química , Proteínas de la Matriz Extracelular/genética , Ciclofilinas/metabolismo , Ciclofilinas/química , Ciclofilinas/genética , Dominio Catalítico , Isomerasa de Peptidilprolil/metabolismo , Isomerasa de Peptidilprolil/química , Isomerasa de Peptidilprolil/genética , Procesamiento Proteico-Postraduccional , Sitios de Unión , Unión Proteica , Autoantígenos/metabolismo , Autoantígenos/química , Autoantígenos/genética , Modelos Moleculares , Mutación , Osteogénesis Imperfecta/metabolismo , Osteogénesis Imperfecta/genética , Procolágeno-Prolina Dioxigenasa/metabolismo , Procolágeno-Prolina Dioxigenasa/genética , Procolágeno-Prolina Dioxigenasa/química , Glicoproteínas de Membrana , Proteoglicanos , Chaperonas Moleculares , Prolil HidroxilasasRESUMEN
Y-box binding protein 1 (YB-1) is a well-known oncogene highly expressed in various cancers, including basal-like breast cancer (BLBC). Beyond its role as a transcription factor, YB-1 is newly defined as an epigenetic regulator involving RNA 5-methylcytosine. However, its specific targets and pro-cancer functions are poorly defined. Here, based on clinical database, we demonstrate a positive correlation between Kruppel-like factor 5 (KLF5) and YB-1 expression in breast cancer patients, but a negative correlation with that of Dachshund homolog 1 (DACH1). Mechanistically, YB-1 enhances KLF5 expression not only through transcriptional activation that can be inhibited by DACH1, but also by stabilizing KLF5 mRNA in a RNA 5-methylcytosine modification-dependent manner. Additionally, ribosomal S6 kinase 2 (RSK2) mediated YB-1 phosphorylation at Ser102 promotes YB-1/KLF5 transcriptional complex formation, which co-regulates the expression of BLBC specific genes, Keratin 16 (KRT16) and lymphocyte antigen 6 family member D (Ly6D), to promote cancer cell proliferation. The RSK inhibitor, LJH685, suppressed BLBC cell tumourigenesis in vivo by disturbing YB-1-KLF5 axis. Our data suggest that YB-1 positively regulates KLF5 at multiple levels to promote BLBC progression. The novel RSK2-YB-1-KLF5-KRT16/Ly6D axis provides candidate diagnostic markers and therapeutic targets for BLBC.