RFWD3 promotes ZRANB3 recruitment to regulate the remodeling of stalled replication forks.

Replication fork reversal is an important mechanism to protect the stability of stalled forks and thereby preserve genomic integrity. While multiple enzymes have been identified that can remodel forks, their regulation remains poorly understood. Here, we demonstrate that the ubiquitin ligase RFWD3, whose mutation causes Fanconi Anemia, promotes recruitment of the DNA translocase ZRANB3 to stalled replication forks and ubiquitinated sites of DNA damage. Using electron microscopy, we show that RFWD3 stimulates fork remodeling in a ZRANB3-epistatic manner. Fork reversal is known to promote nascent DNA degradation in BRCA2-deficient cells. Consistent with a role for RFWD3 in fork reversal, inactivation of RFWD3 in these cells rescues fork degradation and collapse, analogous to ZRANB3 inactivation. RFWD3 loss impairs ZRANB3 localization to spontaneous nuclear foci induced by inhibition of the PCNA deubiquitinase USP1. We demonstrate that RFWD3 promotes PCNA ubiquitination and interaction with ZRANB3, providing a mechanism for RFWD3-dependent recruitment of ZRANB3. Together, these results uncover a new role for RFWD3 in regulating ZRANB3-dependent fork remodeling.

External ankle taping does not alter lower extremity side-step cut and straight sprint biomechanics in young adult males.

Lateral ankle sprains (LAS) are one of the most common musculoskeletal injuries and as a response, clinicians often use external ankle taping prophylactically to reduce the prevalence of injuries. External ankle taping techniques have been shown to significantly reduce passive ankle range of motion; however, there is limited research on the effects of external ankle taping on lower extremity kinematics or kinetics during sport specific tasks. Therefore, our objective was to compare the effects of external ankle taping on ankle, knee and hip kinematics and kinetics compared to no taping during an anticipated sidestep cutting task and a straight sprint task. We conducted a cross-over laboratory study with 16 healthy males. Three-dimensional kinematics and kinetics were collected with a motion capture system and in-ground force plate during 5 trials of a sprint and anticipated side-step cut with or without external ankle taping. Group means and associated 90% confidence intervals were plotted across 100 data points for each task, significance being identified when the confidence intervals did not overlap for three consecutive data points. No significant kinetic or kinematic differences were identified between conditions for the tasks. External ankle taping does not influence lower extremity biomechanics during a control cutting task.

Genomically informed small-molecule drugs overcome resistance to a sustained-release formulation of an engineered death receptor agonist in patient-derived tumor models.

Extrinsic pathway agonists have failed repeatedly in the clinic for three core reasons: Inefficient ligand-induced receptor multimerization, poor pharmacokinetic properties, and tumor intrinsic resistance. Here, we address these factors by (i) using a highly potent death receptor agonist (DRA), (ii) developing an injectable depot for sustained DRA delivery, and (iii) leveraging a CRISPR-Cas9 knockout screen in DRA-resistant colorectal cancer (CRC) cells to identify functional drivers of resistance. Pharmacological blockade of XIAP and BCL-XL by targeted small-molecule drugs strongly enhanced the antitumor activity of DRA in CRC cell lines. Recombinant fusion of the DRA to a thermally responsive elastin-like polypeptide (ELP) creates a gel-like depot upon subcutaneous injection that abolishes tumors in DRA-sensitive Colo205 mouse xenografts. Combination of ELPdepot-DRA with BCL-XL and/or XIAP inhibitors led to tumor growth inhibition and extended survival in DRA-resistant patient-derived xenografts. This strategy provides a precision medicine approach to overcome similar challenges with other protein-based cancer therapies.