RESUMEN
The loading of peptide Ags onto MHC class I molecules is a highly controlled process in which the MHC class I-dedicated chaperone tapasin is a key player. We recently identified a tapasin-related molecule, TAPBPR, as an additional component in the MHC class I Ag-presentation pathway. In this study, we show that the amino acid residues important for tapasin to interact with MHC class I are highly conserved on TAPBPR. We identify specific residues in the N-terminal and C-terminal domains of TAPBPR involved in associating with MHC class I. Furthermore, we demonstrate that residues on MHC class I crucial for its association with tapasin, such as T134, are also essential for its interaction with TAPBPR. Taken together, the data indicate that TAPBPR and tapasin bind in a similar orientation to the same face of MHC class I. In the absence of tapasin, the association of MHC class I with TAPBPR is increased. However, in the absence of TAPBPR, the interaction between MHC class I and tapasin does not increase. In light of our findings, previous data determining the function of tapasin in the MHC class I Ag-processing and presentation pathway must be re-evaluated.
Asunto(s)
Antígeno HLA-A2/metabolismo , Inmunoglobulinas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Secuencia de Aminoácidos , Presentación de Antígeno , Células HEK293 , Antígeno HLA-A2/genética , Células HeLa , Humanos , Inmunoglobulinas/genética , Proteínas de la Membrana/genética , Proteínas de Transporte de Membrana/genética , Datos de Secuencia Molecular , Unión Proteica/genética , Conformación Proteica , Dominios y Motivos de Interacción de Proteínas/genética , ARN Interferente Pequeño/genéticaRESUMEN
RNA helicases remodel the spliceosome to enable pre-mRNA splicing, but their binding and mechanism of action remain poorly understood. To define helicase-RNA contacts in specific spliceosomal states, we develop purified spliceosome iCLIP (psiCLIP), which reveals dynamic helicase-RNA contacts during splicing catalysis. The helicase Prp16 binds along the entire available single-stranded RNA region between the branchpoint and 3'-splice site, while Prp22 binds diffusely downstream of the branchpoint before exon ligation, but then switches to more narrow binding in the downstream exon after exon ligation, arguing against a mechanism of processive translocation. Depletion of the exon-ligation factor Prp18 destabilizes Prp22 binding to the pre-mRNA, suggesting that proofreading by Prp22 may sense the stability of the spliceosome during exon ligation. Thus, psiCLIP complements structural studies by providing key insights into the binding and proofreading activity of spliceosomal RNA helicases.
Asunto(s)
Exones , ARN Helicasas/química , ARN Helicasas/metabolismo , Precursores del ARN/metabolismo , Empalme del ARN , Proteínas de Saccharomyces cerevisiae/metabolismo , Empalmosomas/metabolismo , Adenosina Trifosfatasas/química , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Autoantígenos/química , Autoantígenos/metabolismo , Microscopía por Crioelectrón , ARN Helicasas DEAD-box/química , ARN Helicasas DEAD-box/metabolismo , Modelos Moleculares , Precursores del ARN/química , Factores de Empalme de ARN/genética , Factores de Empalme de ARN/metabolismo , ARN de Hongos/metabolismo , Proteínas Recombinantes , Ribonucleoproteína Nuclear Pequeña U5/química , Ribonucleoproteína Nuclear Pequeña U5/genética , Ribonucleoproteína Nuclear Pequeña U5/metabolismo , Ribonucleoproteínas Nucleares Pequeñas/química , Ribonucleoproteínas Nucleares Pequeñas/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Empalmosomas/químicaRESUMEN
While DNA's perpetual role in biology and life science is well documented, its burgeoning digital applications are beginning to garner significant interest. As the development of novel technologies requires continuous research, product development, startup creation, and financing, this work provides an overview of each respective area and highlights current trends, challenges, and opportunities. These are supported by numerous interviews with key opinion leaders from across academia, government agencies and the commercial sector, as well as investment data analysis. Our findings illustrate the societal and economic need for technological innovation and disruption in data storage, paving the way for nature's own time-tested, advantageous, and unrivaled solution. We anticipate a significant increase in available investment capital and continuous scientific progress, creating a ripe environment on which DNA data storage-enabling startups can capitalize to bring DNA data storage into daily life.