Structural insights into PPP2R5A degradation by HIV-1 Vif.

HIV-1 Vif recruits host cullin-RING-E3 ubiquitin ligase and CBFβ to degrade the cellular APOBEC3 antiviral proteins through diverse interactions. Recent evidence has shown that Vif also degrades the regulatory subunits PPP2R5(A-E) of cellular protein phosphatase 2A to induce G2/M cell cycle arrest. As PPP2R5 proteins bear no functional or structural resemblance to A3s, it is unclear how Vif can recognize different sets of proteins.

Serine protease homolog pairs CLIPA4-A6, A4-A7Δ, and A4-A12 act as cofactors for proteolytic activation of prophenoloxidase-2 and -7 in Anopheles gambiae.

Phenoloxidase (PO) catalyzed melanization and other insect immune responses are mediated by serine proteases (SPs) and their noncatalytic homologs (SPHs). Many of these SP-like proteins have a regulatory clip domain and are called CLIPs. In most insects studied so far, PO precursors are activated by a PAP (i.

The capsid lattice engages a bipartite NUP153 motif to mediate nuclear entry of HIV-1 cores.

Increasing evidence has suggested that the HIV-1 capsid enters the nucleus in a largely assembled, intact form. However, not much is known about how the cone-shaped capsid interacts with the nucleoporins (NUPs) in the nuclear pore for crossing the nuclear pore complex. Here, we elucidate how NUP153 binds HIV-1 capsid by engaging the assembled capsid protein (CA) lattice.

Structural basis for recruitment of host CypA and E3 ubiquitin ligase by maedi-visna virus Vif.

Lentiviral Vif molecules target the host antiviral APOBEC3 proteins for destruction in cellular ubiquitin-proteasome pathways. Different lentiviral Vifs have evolved to use the same canonical E3 ubiquitin ligase complexes, along with distinct noncanonical host cofactors for their activities. Unlike primate lentiviral Vif, which recruits CBFβ as the noncanonical cofactor, nonprimate lentiviral Vif proteins have developed different cofactor recruitment mechanisms.

Cadmium chloride exposure impairs the growth and behavior of Drosophila via ferroptosis.

Cadmium (Cd) is a widely distributed toxic heavy metal that enters the environment via anthropogenic mobilization and accumulates in plants and animals, causing metabolic abnormalities even mortality. Although the toxic effects and stress damage of cadmium have been investigated extensively over the past few decades, research on its ability to trigger ferroptosis, growth retardation, and behavioral abnormalities is insufficient. As a result, the effects of CdCl exposure on growth and development, activity and sleep, and ferroptosis in this study were examined in fruit fly (Drosophila melanogaster).

Preferential binding of DAP-PGs by major peptidoglycan recognition proteins found in cell-free hemolymph of Manduca sexta.

Peptidoglycan recognition proteins (PGRPs) detect invading bacteria to trigger or modulate immune responses in insects. While these roles are established in Drosophila, functional studies are not yet achieved at the PGRP family level in other insects. To attain this goal, we selected Manduca sexta PGRP12 and five of the nine secreted PGRPs for recombinant expression and biochemical characterization.

Function and Cryo-EM structures of broadly potent bispecific antibodies against multiple SARS-CoV-2 Omicron sublineages.

The SARS-CoV-2 variant, Omicron (B.1.1.

Monospecific and bispecific monoclonal SARS-CoV-2 neutralizing antibodies that maintain potency against B.1.617.

COVID-19 pathogen SARS-CoV-2 has infected hundreds of millions and caused over 5 million deaths to date. Although multiple vaccines are available, breakthrough infections occur especially by emerging variants. Effective therapeutic options such as monoclonal antibodies (mAbs) are still critical.

Monospecific and bispecific monoclonal SARS-CoV-2 neutralizing antibodies that maintain potency against B.1.617.

COVID-19 pathogen SARS-CoV-2 has infected hundreds of millions and caused over 5 million deaths to date. Although multiple vaccines are available, breakthrough infections occur especially by emerging variants. Effective therapeutic options such as monoclonal antibodies (mAbs) are still critical.

Rapid, reliable, and reproducible cell fusion assay to quantify SARS-Cov-2 spike interaction with hACE2.

COVID-19 is a global crisis of unimagined dimensions. Currently, Remedesivir is only fully licensed FDA therapeutic. A major target of the vaccine effort is the SARS-CoV-2 spike-hACE2 interaction, and assessment of efficacy relies on time consuming neutralization assay.

Optimization of Porphyran Extraction from by Response Surface Methodology and Its Lipid-Lowering Effects.

Macroalgae polysaccharides are phytochemicals that are beneficial to human health. In this study, response surface methodology was applied to optimize the extraction procedure of porphyran (PYP). The optimum extraction parameters were: 100 °C (temperature), 120 min (time), and 29.

Maedi-visna virus Vif protein uses motifs distinct from HIV-1 Vif to bind zinc and the cofactor required for A3 degradation.

The mammalian apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3 or A3) family of cytidine deaminases restrict viral infections by mutating viral DNA and impeding reverse transcription. To overcome this antiviral activity, most lentiviruses express a viral accessory protein called the virion infectivity factor (Vif), which recruits A3 proteins to cullin-RING E3 ubiquitin ligases such as cullin-5 (Cul5) for ubiquitylation and subsequent proteasomal degradation. Although Vif proteins from primate lentiviruses such as HIV-1 utilize the transcription factor core-binding factor subunit beta as a noncanonical cofactor to stabilize the complex, the maedi-visna virus (MVV) Vif hijacks cyclophilin A (CypA) instead.

Nonstructural Protein 1 of SARS-CoV-2 Is a Potent Pathogenicity Factor Redirecting Host Protein Synthesis Machinery toward Viral RNA.

The causative virus of the COVID-19 pandemic, SARS-CoV-2, uses its nonstructural protein 1 (Nsp1) to suppress cellular, but not viral, protein synthesis through yet unknown mechanisms. We show here that among all viral proteins, Nsp1 has the largest impact on host viability in the cells of human lung origin. Differential expression analysis of mRNA-seq data revealed that Nsp1 broadly alters the cellular transcriptome.

Multifaceted HIV-1 Vif interactions with human E3 ubiquitin ligase and APOBEC3s.

APOBEC3 (A3) proteins are a family of host antiviral restriction factors that potently inhibit various retroviral infections, including human immunodeficiency virus (HIV)-1. To overcome this restriction, HIV-1 virion infectivity factor (Vif) recruits the cellular cofactor CBFβ to assist in targeting A3 proteins to a host E3 ligase complex for polyubiquitination and subsequent proteasomal degradation. Intervention of the Vif-A3 interactions could be a promising therapeutic strategy to facilitate A3-mediated suppression of HIV-1 in patients.

Structural basis of antagonism of human APOBEC3F by HIV-1 Vif.

HIV-1 virion infectivity factor (Vif) promotes degradation of the antiviral APOBEC3 (A3) proteins through the host ubiquitin-proteasome pathway to enable viral immune evasion. Disrupting Vif-A3 interactions to reinstate the A3-catalyzed suppression of human immunodeficiency virus type 1 (HIV-1) replication is a potential approach for antiviral therapeutics. However, the molecular mechanisms by which Vif recognizes A3 proteins remain elusive.

APOBEC3A Loop 1 Is a Determinant for Single-Stranded DNA Binding and Deamination.

The apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3 or A3) family of proteins functions in the innate immune system. The A3 proteins are interferon inducible and hypermutate deoxycytidine to deoxyuridine in foreign single-stranded DNA (ssDNA). However, this deaminase activity cannot discriminate between foreign and host ssDNA at the biochemical level, which presents a significant danger when A3 proteins gain access to the nucleus.

The three-dimensional structure and recognition mechanism of Manduca sexta peptidoglycan recognition protein-1.

Peptidoglycan recognition proteins (PGRPs) recognize bacteria through their unique cell wall constituent, peptidoglycans (PGs). PGRPs are conserved from insects to mammals and all function in antibacterial defense. In the tobacco hornworm Manduca sexta, PGRP1 and microbe binding protein (MBP) interact with PGs and hemolymph protease-14 precursor (proHP14) to yield active HP14.

Manduca sexta hemolymph protease-2 (HP2) activated by HP14 generates prophenoloxidase-activating protease-2 (PAP2) in wandering larvae and pupae.

Melanization is a universal defense mechanism of insects against microbial infection. During this response, phenoloxidase (PO) is activated from its precursor by prophenoloxidase activating protease (PAP), the terminal enzyme of a serine protease (SP) cascade. In the tobacco hornworm Manduca sexta, hemolymph protease-14 (HP14) is autoactivated from proHP14 to initiate the protease cascade after host proteins recognize invading pathogens.

Multifaceted biological insights from a draft genome sequence of the tobacco hornworm moth, Manduca sexta.

Manduca sexta, known as the tobacco hornworm or Carolina sphinx moth, is a lepidopteran insect that is used extensively as a model system for research in insect biochemistry, physiology, neurobiology, development, and immunity. One important benefit of this species as an experimental model is its extremely large size, reaching more than 10 g in the larval stage. M.

The structure of a prophenoloxidase (PPO) from Anopheles gambiae provides new insights into the mechanism of PPO activation.

Background: Phenoloxidase (PO)-catalyzed melanization is a universal defense mechanism of insects against pathogenic and parasitic infections. In mosquitos such as Anopheles gambiae, melanotic encapsulation is a resistance mechanism against certain parasites that cause malaria and filariasis. PO is initially synthesized by hemocytes and released into hemolymph as inactive prophenoloxidase (PPO), which is activated by a serine protease cascade upon recognition of foreign invaders.

The immune signaling pathways of Manduca sexta.

Signal transduction pathways and their coordination are critically important for proper functioning of animal immune systems. Our knowledge of the constituents of the intracellular signaling network in insects mainly comes from genetic analyses in Drosophila melanogaster. To facilitate future studies of similar systems in the tobacco hornworm and other lepidopteran insects, we have identified and examined the homologous genes in the genome of Manduca sexta.

A genome-wide analysis of antimicrobial effector genes and their transcription patterns in Manduca sexta.

Antimicrobial proteins/peptides (AMPs) are effectors of innate immune systems against pathogen infection in multicellular organisms. Over half of the AMPs reported so far come from insects, and these effectors act in concert to suppress or kill bacteria, fungi, viruses, and parasites. In this work, we have identified 86 AMP genes in the Manduca sexta genome, most of which seem likely to be functional.

Structural features, evolutionary relationships, and transcriptional regulation of C-type lectin-domain proteins in Manduca sexta.

C-type lectins (CTLs) are a large family of Ca(2+)-dependent carbohydrate-binding proteins recognizing various glycoconjugates and functioning primarily in immunity and cell adhesion. We have identified 34 CTLDP (for CTL-domain protein) genes in the Manduca sexta genome, which encode proteins with one to three CTL domains. CTL-S1 through S9 (S for simple) have one or three CTL domains; immulectin-1 through 19 have two CTL domains; CTL-X1 through X6 (X for complex) have one or two CTL domains along with other structural modules.

Sequence conservation, phylogenetic relationships, and expression profiles of nondigestive serine proteases and serine protease homologs in Manduca sexta.

Serine protease (SP) and serine protease homolog (SPH) genes in insects encode a large family of proteins involved in digestion, development, immunity, and other processes. While 68 digestive SPs and their close homologs are reported in a companion paper (Kuwar et al., in preparation), we have identified 125 other SPs/SPHs in Manduca sexta and studied their structure, evolution, and expression.