Insights into BTB-Cul3 Ubiquitin Ligases from the Structures of SPOP-Substrate Complexes

Cullin-Ring ubiquitin ligases (CRLs) are E3 complexes that specifically recognize substrates through substrate adaptors. In the largest CRL subfamily, Cul3 binds a BTB domain, and a protein-interaction domain such as MATH recruits substrates for ubiquitination. Here we present biochemical and structural analyses of the MATH and BTB domain containing protein, SPOP, which regulates diverse signaling pathways. First, we identified a conserved SPOP Binding Consensus (SBC) motif in the transcriptional regulator Ci, the protein phosphatase Puc, and the chromatin component MacroH2A. The SBC motif specifically binds the MATH domain of SPOP, and is required for Puc ubiquitination in vitro and in vivo. Structural determination and analysis of SPOPMATH in complex with peptides encompassing the SBC motif revealed the molecular basis for recognition of diverse substrates by SPOP. Second, the dimeric BTB domain of SPOP assembles into a dimer with Cul3, an interaction that is facilitated by a helical motif that we term 3-box due to resemblance to F- and SOCS-boxes in other cullin-based E3s. 3-box is also found in the BTB protein Gigaxonin and is predicted in a subset of BTB proteins. Furthermore, structures of nearly full-length SPOP constructs indicate flexibility between the MATH and BTB domains, potentially allowing regulation of diverse substrates. Those such as Puc with multiple SBCs may functionally interact with a single SPOP dimer. All together, this study provides a molecular understanding of how MATH-BTB proteins recruit substrates to Cul3, and how their dimerization and structural variability may facilitate recognition and ubiquitination of diverse substrates

Well-balanced fifth-order finite difference Hermite WENO scheme for the shallow water equations

In this paper, we propose a well-balanced fifth-order finite difference Hermite WENO (HWENO) scheme for the shallow water equations with non-flat bottom topography in pre-balanced form. For achieving the well-balance property, we adopt the similar idea of WENO-XS scheme [Xing and Shu, J. Comput. Phys., 208 (2005), 206-227.] to balance the flux gradients and the source terms. The fluxes in the original equation are reconstructed by the nonlinear HWENO reconstructions while other fluxes in the derivative equations are approximated by the high-degree polynomials directly. And an HWENO limiter is applied for the derivatives of equilibrium variables in time discretization step to control spurious oscillations which maintains the well-balance property. Instead of using a five-point stencil in the same fifth-order WENO-XS scheme, the proposed HWENO scheme only needs a compact three-point stencil in the reconstruction. Various benchmark examples in one and two dimensions are presented to show the HWENO scheme is fifth-order accuracy, preserves steady-state solution, has better resolution, is more accurate and efficient, and is essentially non-oscillatory.Comment: 24 pages, 11 figure

Superadditivity in trade-off capacities of quantum channels

In this article, we investigate the additivity phenomenon in the dynamic capacity of a quantum channel for trading classical communication, quantum communication and entanglement. Understanding such additivity property is important if we want to optimally use a quantum channel for general communication purpose. However, in a lot of cases, the channel one will be using only has an additive single or double resource capacity, and it is largely unknown if this could lead to an superadditive double or triple resource capacity. For example, if a channel has an additive classical and quantum capacity, can the classical-quantum capacity be superadditive? In this work, we answer such questions affirmatively. We give proof-of-principle requirements for these channels to exist. In most cases, we can provide an explicit construction of these quantum channels. The existence of these superadditive phenomena is surprising in contrast to the result that the additivity of both classical-entanglement and classical-quantum capacity regions imply the additivity of the triple capacity region.Comment: 15 pages. v2: typo correcte

COVID-19 Patients with Concurrent Acute Angle-Closure Glaucoma: A Retrospective Hospital Study.”

This retrospective study investigates the interaction between COVID-19 and Acute Angle-Closure Glaucoma (AACG), analyzing clinical features, laboratory fndings, and OCTAimages in 20 patients diagnosed with both conditions. Elevated Intraocular Pressure (IOP) levels and a decrease in the deep capillary plexus (DCP) and choriocapillaris (CC) foveal vessel density were observed, with infammation and coagulation markers also elevated. These fndings suggest that the physiological changes induced by COVID-19 may exacerbate AACG symptoms. Despite the study’s limitations, including a small sample size and retrospective design, these insights are pivotal for clinicians and underline the importance of careful ocular monitoring in COVID-19 patients. Further research is warranted to explore the long-term implica-tions of these fndings and the mechanistic pathways underlying the interaction between COVID-19 andAACG