SUMMARY The eukaryotic chaperonin TRiC/CCT uses ATP cycling to fold many essential proteins that other chaperones cannot fold. This 1 MDa hetero-oligomer consists of two identical stacked rings assembled from eight paralogous subunits, each containing a conserved ATP-binding domain. Here, we report a dramatic asymmetry in the ATP utilization cycle of this ring-shaped chaperonin, despite its apparently symmetric architecture. Only four of the eight different subunits bind ATP at physiological concentrations. ATP binding and hydrolysis by the low-affinity subunits is fully dispensable for TRiC function in vivo. The conserved nucleotide-binding hierarchy among TRiC subunits is evolutionarily modulated through differential nucleoside contacts. Strikingly, high-and low-affinity subunits are spatially segregated within two contiguous hemispheres in the ring, generating an asymmetric power stroke that drives the folding cycle. This unusual mode of ATP utilization likely serves to orchestrate a directional mechanism underlying TRiC/CCT’s unique ability to fold complex eukaryotic proteins.

During terminal differentiation, the global protein complement is remodeled, as epitomized by erythrocytes, whose cytosol is ~98% globin. The erythroid proteome undergoes a rapid transition at the reticulocyte stage; however, the mechanisms driving programmed elimination of preexisting cytosolic proteins are unclear. We found that a mutation in the murine Ube2o gene, which encodes a ubiquitin-conjugating enzyme induced during erythropoiesis, results in anemia. Proteomic analysis suggested that UBE2O is a broad-spectrum ubiquitinating enzyme that remodels the erythroid proteome. In particular, ribosome elimination, a hallmark of reticulocyte differentiation, was defective in Ube2o−/− mutants. UBE2O recognized ribosomal proteins and other substrates directly, targeting them to proteasomes for degradation. Thus, in reticulocytes, the induction of ubiquitinating factors may drive the transition from a complex to a simple proteome.

IMPORTANCETransoral robotic surgery has been widely adopted since approval by the US Food and Drug Administration in December 2009, despite limited comparative data.OBJECTIVE To compare the long-term outcomes of transoral robotic surgery with those of nonrobotic surgery for patients with early-stage oropharyngeal cancer. DESIGN, SETTING, AND PARTICIPANTSA retrospective cohort comparative effectiveness analysis was performed of patients in the National Cancer Database with clinical T1 and T2 oropharyngeal squamous cell carcinoma diagnosed between January 1, 2010, and December 31, 2015, who underwent definitive robotic and nonrobotic surgery. Multivariable Cox proportional hazards regression analysis and propensity score matching were performed in patients with known human papillomavirus status to adjust for patient-and disease-related covariates. Survival after robotic and nonrobotic surgery was also compared in 3 unrelated cancers: prostate, endometrial, and cervical cancer. Statistical analysis was performed from April 10, 2019, to May 21, 2020. MAIN OUTCOMES AND MEASURES Overall survival.RESULTS Of 9745 patients (7652 men [78.5%]; mean [SD] age, 58.8 [9.6] years) who met inclusion criteria, 2694 (27.6%) underwent transoral robotic surgery. There was a significant increase in the use of robotic surgery from 18.3% (240 of 1309) to 35.5% (654 of 1841) of all surgical procedures for T1 and T2 oropharyngeal cancers from 2010 to 2015 (P = .003). Robotic surgery was associated with lower rates of positive surgical margins (12.5% [218 of 1746] vs 20.3% [471 of 2325]; P < .001) and lower use of adjuvant chemoradiotherapy (28.6% [500 of 1746] vs 35.7% [831 of 2325]; P < .001). Among 4071 patients with known human papillomavirus status, robotic surgery was associated with improved overall survival compared with nonrobotic surgery in multivariable Cox proportional hazards regression (hazard ratio [HR], 0.74; 95 CI, 0.61-0.90; P = .002). Similar results were seen when analyzing only the subset of facilities offering both robotic and nonrobotic surgery. The 5-year overall survival was 84.8% vs 80.3% among patients undergoing robotic vs nonrobotic surgery in propensity score-matched cohorts (P = .001). By contrast, there was no evidence that robotic surgery was associated with improved survival in other cancers, such as prostate cancer (HR, 0.92; 95% CI, 0.79-1.07; P = .26), endometrial cancer (HR, 0.97; 95% CI, 0.90-1.04; P = .36), and cervical cancer (HR, 1.27; 95% CI, 0.96-1.69; P = .10). CONCLUSIONS AND RELEVANCEThis study suggests that transoral robotic surgery was associated with improved surgical outcomes and survival compared with nonrobotic surgery in patients with early-stage oropharyngeal cancer. Evaluation in comparative randomized trials is warranted.

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The current shortage of primary care physicians (PCPs), particularly as more individuals obtain health insurance and seek primary care services, is a growing national concern. The Crimson Care Collaborative (CCC) is a joint student-faculty initiative in post-health-care-reform Massachusetts that was started with the explicit goal of attracting medical students to primary care careers. It fills a niche for student-run clinics, providing evening access to primary care services for patients without a PCP and urgent care services for patients of a Massachusetts General Hospital-affiliated internal medicine clinic, with the aim of decreasing emergency department use in both groups. Unlike other student-run clinics, CCC is integrated into the mainstream health care structure of an existing primary care clinic and, because of universal health insurance coverage in Massachusetts, can bill for its services. In addition to the clinical services offered, the student-run research team evaluates the quality of care and the patients' experiences at the clinic. This article describes the creation and development of CCC, including a brief overview of clinic operations, social services, research, laboratory services, student and patient education programs, and finance. In the wake of the Patient Protection and Affordable Care Act of 2010, CCC is an example of how students can aid the transition to universal health care in the United States and how medical schools can expose students early in their training to primary care and clinic operations.

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Breast irradiation has long been utilized in the adjuvant or metastatic setting to eliminate microscopic disease or to palliate existing disease, respectively. However, preclinical data have demonstrated that radiation can also alter the tumor microenvironment and induce antitumor immune responses. As a result, multiple clinical studies have been undertaken and have reported synergy between radiation and immune checkpoint blockade across various cancer types. Given recent clinical successes with immune checkpoint blockade in both early-stage and metastatic breast cancer, there has been substantial interest in combining radiation and immunotherapy to enhance local and systemic immune responses. Herein, we review the preclinical rationale for combining radiotherapy and immunotherapy, the early clinical trials that have adopted this strategy in breast cancer, and the landscape of ongoing relevant clinical trials. Finally, we propose future directions based on promising preclinical studies that integrate radiation, checkpoint blockade, and novel agents for the treatment of breast cancer.