K63-Linked Ubiquitin Is Required for Restriction of HIV-1 Reverse Transcription and Capsid Destabilization by Rhesus TRIM5α.

TRIM5α is an antiviral restriction factor that inhibits retroviral infection in a species-specific fashion. TRIM5α binds to and forms assemblies around the retroviral capsid. Following binding, poorly understood, ubiquitin-dependent events lead to the disassembly of the viral core, prior to the accumulation of viral reverse transcription products in the target cell. It is also known that assemblies of TRIM5α and other TRIM family proteins can be targets of autophagic degradation. The goal of this study was to define the role of specific ubiquitin linkages in the retroviral restriction and autophagic degradation of TRIM5α and delineate any connection between these two processes. To this end, we generated fusion proteins in which the catalytic domains of different deubiquitinase (DUB) enzymes, with different specificities for polyubiquitinated linkages, were fused to the N-terminal RING domain of Rhesus macaque TRIM5α. We assessed the role of ubiquitination in restriction and the degree to which specific types of ubiquitination are required for the association of TRIM5α with autophagic proteins. We determined that K63-linked ubiquitination by TRIM5α is required to induce capsid disassembly and to inhibit reverse transcription of HIV, while the ability to inhibit HIV-1 infection was not dependent on K63-linked ubiquitination. We also observed that K63-linked ubiquitination is required for the association of TRIM5α with autophagosomal membranes and the autophagic adapter protein p62.IMPORTANCE Although the mechanisms by which TRIM5α can induce the abortive disassembly of retroviral capsids have remained obscure, numerous studies have suggested a role for ubiquitination and cellular degradative pathways. These studies have typically relied on global perturbation of cellular degradative pathways. Here, through the use of linkage-specific deubiquitinating enzymes tethered to TRIM5α, we delineate the ubiquitin linkages which drive specific steps in restriction and degradation by TRIM5α, providing evidence for a noncanonical role for K63-linked ubiquitin in the process of retroviral restriction by TRIM5α and potentially providing insight into the mechanism of action of other TRIM family proteins.

Privacy, or the Lack Thereof, and Its Implications for Dignity in Mobile COVID-19 Testing.

INTRODUCTION: Chicago's COVID-19 Rapid Response Team (CRRT) is a decentralized, interprofessional group of nurses, residents, students, and faculty who provide free COVID-19 testing for those living or working in congregate settings (i.e., shelters, long term care facilities, prisons and encampments) due to their increased risk. Individuals within these vulnerable populations regularly experience stigma, a lack of privacy, and healthcare discrimination as they are often in low-income and underserved communities. The CRRT tests in settings that are necessarily large (cafeterias, meeting areas, gymnasiums, recreation rooms), and provide little physical privacy. Regardless of patient circumstances, respecting patient dignity is a professional standard of care, and patient privacy is consistent with that standard. METHODS: Guided by trauma-informed care techniques, emancipatory nursing practice, and cultural safety methodology, student members of the CRRT initiated a project focused on expanding physical privacy protection for those undergoing COVID-19 testing. CONCLUSION: Though the introduction of a portable privacy screen started as an initiative to safeguard the dignity for underserved populations, this call to action implores current and future health care providers to prioritize the ethical treatment of those most vulnerable by advocating for patient dignity and privacy.