RESUMO
Stalled ribosomes at the endoplasmic reticulum (ER) are covalently modified with the ubiquitin-like protein UFM1 on the 60S ribosomal subunit protein RPL26 (also known as uL24)1,2. This modification, which is known as UFMylation, is orchestrated by the UFM1 ribosome E3 ligase (UREL) complex, comprising UFL1, UFBP1 and CDK5RAP3 (ref. 3). However, the catalytic mechanism of UREL and the functional consequences of UFMylation are unclear. Here we present cryo-electron microscopy structures of UREL bound to 60S ribosomes, revealing the basis of its substrate specificity. UREL wraps around the 60S subunit to form a C-shaped clamp architecture that blocks the tRNA-binding sites at one end, and the peptide exit tunnel at the other. A UFL1 loop inserts into and remodels the peptidyl transferase centre. These features of UREL suggest a crucial function for UFMylation in the release and recycling of stalled or terminated ribosomes from the ER membrane. In the absence of functional UREL, 60S-SEC61 translocon complexes accumulate at the ER membrane, demonstrating that UFMylation is necessary for releasing SEC61 from 60S subunits. Notably, this release is facilitated by a functional switch of UREL from a 'writer' to a 'reader' module that recognizes its product-UFMylated 60S ribosomes. Collectively, we identify a fundamental role for UREL in dissociating 60S subunits from the SEC61 translocon and the basis for UFMylation in regulating protein homeostasis at the ER.
Assuntos
Retículo Endoplasmático , Processamento de Proteína Pós-Traducional , Subunidades Ribossômicas Maiores de Eucariotos , Ubiquitina-Proteína Ligases , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sítios de Ligação , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/ultraestrutura , Microscopia Crioeletrônica , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/ultraestrutura , Homeostase , Membranas Intracelulares/metabolismo , Peptidil Transferases/química , Peptidil Transferases/metabolismo , Peptidil Transferases/ultraestrutura , Proteínas Ribossômicas/química , Proteínas Ribossômicas/metabolismo , Proteínas Ribossômicas/ultraestrutura , RNA de Transferência/metabolismo , Canais de Translocação SEC/química , Canais de Translocação SEC/metabolismo , Canais de Translocação SEC/ultraestrutura , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/metabolismo , Proteínas Supressoras de Tumor/ultraestrutura , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/ultraestrutura , Subunidades Ribossômicas Maiores de Eucariotos/química , Subunidades Ribossômicas Maiores de Eucariotos/metabolismo , Subunidades Ribossômicas Maiores de Eucariotos/ultraestruturaRESUMO
This research aimed to understand the coping and wellbeing of dual-career athletes during the COVID-19 pandemic. A total of 159 dual-career athletes completed a series of questionnaires that aimed to identify the coping strategies and their impact on the wellbeing of respondents during COVID-19 restrictions. The survey included measures of coping, wellbeing, burnout, and identity along with open-ended questions with the focus of change, coping, and support. Findings identified three coping approaches that have been employed by dual-career athletes: positive coping, negative coping, and acceptance. The three coping approaches also showed distinct wellbeing and burnout profiles. The negative coping group showed high indicators of burnout and poor wellbeing, whereas the acceptance group showed the highest scores on wellbeing and low indications of burnout. Based on the findings, it is recommended that dual-career support providers and stakeholders consider how best to support athletes that have not coped well and have experienced wellbeing issues during this time. It is also important to recognise the benefit a dual-career has provided to some individuals during this period.
