Accordingly, mutations in the miR-125b seed sequence abrogated the regulatory effect of the miRNA on the CPSF6 3’UTR. Finally, pull-down experiments demonstrated that miR-125b physically interacts with CPSF6 3’UTR. Interestingly, HIV-1 infection down-regulated miR-125b expression concurrent with up-regulation of CPSF6. Notably, miR-125b down-regulation in infected cells was not due to reduced pri-miRNA or pre-miRNA levels. However, miR-125b down-regulation depended on HIV-1 reverse transcription but not viral DNA integration. These findings establish a post-transcriptional mechanism that controls CPSF6 expression and highlight a novel function of miR-125b during HIV-host interaction. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.Lethal infections by strains of the highly pathogenic avian influenza virus (HPAIV) H5N1 pose serious threats to both the poultry industry and public health worldwide. A lack of confirmed HPAIV epitopes recognized by cytotoxic T lymphocytes (CTLs) has hindered the utilization of CD8+ T cell-mediated immunity and has precluded the development of effectively diversified epitope-based vaccination approaches. In particular, an HPAIV H5N1 CTL-recognized epitope based on the peptide-MHC-I-β2m (pMHC-I) complex has not yet been designed. Here, screening a collection of selected peptides of several HPAIV strains against a specific pathogen-free (SPF) pMHC-I (pBF2*1501), we identified a highly conserved HPAIV H5N1 CTL epitope, named HPAIV-PA123-130 We determined the structure of the BF2*1501-PA123-130 complex at 2.1 Å resolution to elucidate the molecular mechanisms of a preferential presentation of the highly conserved PA123-130 epitope in the chicken B15 lineage. Conformational characteristics of the PA123-130 epitope with a protruding Tyr-7 residue indicated that this epitope has great potential to be recognized by specific TCRs. Moreover, significantly increased numbers of CD8+ T cells specific for the HPAIV-PA123-130 epitope in peptide-immunized chickens indicated that a repertoire of CD8+ T cells can specifically respond to this epitope. We anticipate that the identification and structural characterization of the PA123-130 epitope reported here could enable further studies of CTL immunity against HPAIV H5N1. Such studies may aid in the development of vaccine development strategies using well-conserved internal viral antigens in chickens. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.Heme regulatory motifs (HRMs) are present in many proteins that are involved in diverse biological functions. The C-terminal tail region of human heme oxygenase-2 (HO2) contains two HRMs whose cysteine residues form a disulfide bond; when reduced, these cysteines are available to bind Fe3+-heme. Terfenadine clinical trial Heme binding to the HRMs occurs independently of the HO2 catalytic active site in the core of the protein, where heme binds with high affinity and is degraded to biliverdin. Here, we describe the reversible, protein-mediated transfer of heme between the HRMs and the HO2 core. Using hydrogen-deuterium exchange (HDX)-MS to monitor the dynamics of HO2 with and without Fe3+-heme bound to the HRMs and to the core, we detected conformational changes in the catalytic core only in one state of the catalytic cycle-when Fe3+-heme is bound to the HRMs and the core is in the apo state. These conformational changes were consistent with transfer of heme between binding sites. Indeed, we observed that HRM-bound Fe3+-heme is transferred to the apo-core either upon independent expression of the core and of a construct spanning the HRM-containing tail or after a single turnover of heme at the core. Moreover, we observed transfer of heme from the core to the HRMs and equilibration of heme between the core and HRMs. We therefore propose an Fe3+-heme transfer model in which HRM-bound heme is readily transferred to the catalytic site for degradation to facilitate turnover, but can also equilibrate between the sites to maintain heme homeostasis. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.Over the last several years it has become clear that higher order assemblies on membranes, exemplified by signalosomes, are a paradigm for the regulation of many membrane signaling processes. We have recently combined two-color direct stochastic optical reconstruction microscopy (dSTORM) with the (Clus-DoC) algorithm that combines cluster detection and colocalization analysis to observe the organization of 5-lipoxygenase (5-LO) and 5-lipoxygenase-activating protein (FLAP) into higher order assemblies on the nuclear envelope of mast cells; these assemblies were linked to leukotriene (LT)C4 production. In this study we investigated whether higher order assemblies of 5-LO and FLAP included cytosolic phospholipase A2 (cPLA2) and were linked to LTB4 production in murine neutrophils. Using two- and three-color dSTORM supported by fluorescence lifetime imaging microscopy we identified higher order assemblies containing 40 molecules (median) [IQR 23, 87] of 5-LO, and 53 molecules [62, 156] of FLAP monomer. 98 [18, 154] molecules of cPLA2 were clustered with 5-LO; and 77 [33, 114] molecules of cPLA2 were associated with FLAP. These assemblies were tightly linked to LTB4 formation. The activation-dependent close associations of cPLA2, FLAP and 5-LO in higher order assemblies on the nuclear envelope support a model in which arachidonic acid is generated by cPLA2 in apposition to FLAP, facilitating its transfer to 5-LO to initiate LT synthesis. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.BACKGROUND Immune checkpoint inhibitors (CIs) have revolutionized treatment of advanced melanoma, leading to an emerging population of long-term survivors. Survivors’ quality of life (QOL) and symptom burden are poorly understood. We set out to evaluate symptom burden and QOL in patients with advanced melanoma alive more than 1 year after initiating CI therapy. METHODS Cross-sectional surveys, accompanied by chart review of patients with advanced melanoma treated with CIs at Memorial Sloan Kettering Cancer Center, completed therapy, and were alive >1 year after treatment initiation. Surveys were administered between February and August 2018. Surveys included European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30, EuroQOL, items from Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events and Fatigue Severity Scale. RESULTS We included 90 patients. The most common CI regimens were ipilimumab plus nivolumab (53%) and pembrolizumab (41%); most patients (71%) were not treated in clinical trials.