The accumulation of unfolded proteins under endoplasmic reticulum (ER) stress leads to the activation of the multi-domain protein sensor IRE1α as part of the unfolded protein response (UPR). Clustering of IRE1α lumenal domains in the presence of unfolded proteins promotes kinase trans-autophosphorylation in the cytosol and subsequent RNase domain activation. Interestingly, there is an allosteric relationship between the kinase and RNase domains of IRE1α, which allows ATP-competitive inhibitors to modulate the activity of the RNase domain. Here, we use kinase inhibitors to study how ATP-binding site conformation affects the activity of the RNase domain of IRE1α. We find that diverse ATP-competitive inhibitors of IRE1α promote dimerization and activation of RNase activity despite blocking kinase trans-autophosphorylation. In contrast, a subset of ATP-competitive ligands, which we call KIRAs, allosterically inactivate the RNase domain through the kinase domain by stabilizing monomeric IRE1α. Further insight into how ATP-competitive inhibitors are able to divergently modulate the RNase domain through the kinase domain was gained by obtaining the first structure of apo human IRE1α in the RNase active back-to-back dimer conformation. Comparison of this structure with other existing structures of IRE1α and integration of our extensive structure activity relationship (SAR) data has led us to formulate a model to rationalize how ATP-binding site ligands are able to control IRE1α oligomeric state and subsequent RNase domain activity.

Antibodies that mediate killing of HIV-infected cells through antibody-dependent cellular cytotoxicity (ADCC) have been implicated in protection from HIV infection and disease progression. Despite these observations, these types of HIV antibodies are understudied compared to neutralizing antibodies. Here we describe four monoclonal antibodies (mAbs) obtained from one individual that target the HIV transmembrane protein, gp41, and mediate ADCC activity. These four mAbs arose from independent B cell lineages suggesting that in this individual, multiple B cell responses were induced by the gp41 antigen. Competition and phage peptide display mapping experiments suggested that two of the mAbs target epitopes in the cysteine loop that are highly conserved and a common target of HIV gp41-specific antibodies. The amino acid sequences that bind these mAbs are overlapping but distinct. The two other mAbs were competed by mAbs that target the C-terminal heptad repeat (CHR) and the fusion peptide proximal region (FPPR) and appear to both target a similar unique conformational epitope. These gp41-specific mAbs mediated killing of infected cells that express high levels of Env due to either pre-treatment with interferon or deletion of vpu to increase levels of BST-2/Tetherin. They also mediate killing of target cells coated with various forms of the gp41 protein, including full-length gp41, gp41 ectodomain or a mimetic of the gp41 stump. Unlike many ADCC mAbs that target HIV gp120, these gp41-mAbs are not dependent on Env structural changes associated with membrane-bound CD4 interaction. Overall, the characterization of these four new mAbs that target gp41 and mediate ADCC provides evidence for diverse gp41 B cell lineages with overlapping but distinct epitopes within an individual. Such antibodies that can target various forms of envelope protein could represent a common response to a relatively conserved HIV epitope for a vaccine.

Summary Inducible Hsp70 (Hsp70i) is overexpressed in a wide spectrum of human tumors and its expression correlates with metastasis, poor outcomes, and resistance to chemotherapy in patients. Identification of small molecule inhibitors selective for Hsp70i could provide new therapeutic tools for cancer treatment. In this work, we used fluorescence-linked enzyme chemoproteomic strategy (FLECS) to identify HS-72, an allosteric inhibitor selective for Hsp70i. HS-72 displays the hallmarks of Hsp70 inhibition in cells, promoting substrate protein degradation and growth inhibition. Importantly, HS-72 is selective for Hsp70i over the closely related constitutively active Hsc70. Studies with purified protein show HS-72 acts as an allosteric inhibitor, reducing ATP affinity. In vivo HS-72 is well-tolerated, showing bioavailability and efficacy, inhibiting tumor growth and promoting survival in a HER2+ model of breast cancer. The HS-72 scaffold is amenable to resynthesis and iteration, suggesting an ideal starting point for a new generation of anticancer therapeutics targeting Hsp70i.

Background: Lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals face considerable health disparities, often due to a lack of LGBTQ-competent care. Such disparities and lack of access to informed care are even more staggering in rural settings. As the state medical school for the Washington, Wyoming, Alaska, Montana, and Idaho (WWAMI) region, the University of Washington School of Medicine (UWSOM) is in a unique position to train future physicians to provide healthcare that meets the needs of LGBTQ patients both regionally and nationally. Objective: To describe our methodology of developing a student-driven longitudinal, region-wide curriculum to train medical students to provide high-quality care to LGBTQ patients. Methods: A 4-year LGBTQ Health Pathway was developed and implemented as a student-led initiative at the UWSOM. First- and second-year medical students at sites across the WWAMI region are eligible to apply. Accepted Pathway students complete a diverse set of pre-clinical and clinical components: online modules, didactic courses, longitudinal community service/advocacy work, a scholarly project, and a novel clinical clerkship in LGBTQ health developed specifically for this Pathway experience. Students who complete all requirements receive a certification of Pathway completion. This is incorporated into the Medical Student Performance Evaluation as part of residency applications. Results: The LGBTQ Health Pathway is currently in its fourth year. A total of 43 total students have enrolled, of whom 37.3% are based in the WWAMI region outside of Seattle. Pathway students have completed a variety of scholarly projects on LGBTQ topics, and over 1000 hours of community service/advocacy. The first cohort of 8 students graduated with a certificate of Pathway completion in spring 2020. Conclusions: The LGBTQ Health Pathway at UWSOM is a novel education program for motivated medical students across the 5-state WWAMI region. The diverse milestones, longitudinal nature of the program, focus on rural communities, and opportunities for student leadership are all strengths and unique aspects of this program. The Pathway curriculum and methodology described here serve as a model for student involvement and leadership in medical education. This program enables medical students to enhance their training in the care of LGBTQ patients and provides a unique educational opportunity for future physicians who strive to better serve LGBTQ populations.