Sequence-dependent scale for translocon-mediated insertion of interfacial helices in membranes.

Biological membranes consist of a lipid bilayer studded with integral and peripheral membrane proteins. Most α-helical membrane proteins require protein-conducting insertases known as translocons to assist in their membrane insertion and folding. While the sequence-dependent propensities for a helix to either translocate through the translocon or insert into the membrane have been codified into numerical hydrophobicity scales, the corresponding propensity to partition into the membrane interface remains unrevealed.

Cetylpyridinium chloride promotes disaggregation of SARS-CoV-2 virus-like particles.

Background: SARS-CoV-2 is continuously disseminating worldwide. The development of strategies to break transmission is mandatory.

Aim Of The Study: To investigate the potential of cetylpyridinium chloride (CPC) as a viral inhibitor.

The SARS-CoV-2 envelope (E) protein has evolved towards membrane topology robustness.

-. Single-spanning SARS-CoV-2 envelope (E) protein topology is a major determinant of protein quaternary structure and function. -.

Viral Bcl2s' transmembrane domain interact with host Bcl2 proteins to control cellular apoptosis.

Viral control of programmed cell death relies in part on the expression of viral analogs of the B-cell lymphoma 2 (Bcl2) protein known as viral Bcl2s (vBcl2s). vBcl2s control apoptosis by interacting with host pro- and anti-apoptotic members of the Bcl2 family. Here, we show that the carboxyl-terminal hydrophobic region of herpesviral and poxviral vBcl2s can operate as transmembrane domains (TMDs) and participate in their homo-oligomerization.

A Bimolecular Multicellular Complementation System for the Detection of Syncytium Formation: A New Methodology for the Identification of Nipah Virus Entry Inhibitors.

Fusion of viral and cellular membranes is a key step during the viral life cycle. Enveloped viruses trigger this process by means of specialized viral proteins expressed on their surface, the so-called viral fusion proteins. There are multiple assays to analyze the viral entry including those that focus on the cell-cell fusion induced by some viral proteins.

Dissecting the individual contribution of conserved cysteines to the redox regulation of RubisCO.

Oxidation of the cysteines from ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) leads to inactivation and promotes structural changes that increase the proteolytic sensitivity and membrane association propensity related to its catabolism. To uncover the individual role of the different cysteines, the sequential order of modification under increasing oxidative conditions was determined using chemical labeling and mass spectrometry. Besides, site-directed RubisCO mutants were obtained in Chlamydomonas reinhardtii replacing single conserved cysteines (Cys84, Cys172, Cys192, Cys247, Cys284, Cys427, Cys459 from the large and sCys41, sCys83 from the small subunit) and the redox properties of the mutant enzymes were determined.

Characterization of the inner membrane protein BB0173 from Borrelia burgdorferi.

Background: The bacterial spirochete Borrelia burgdorferi is the causative agent of the most commonly reported arthropod-borne illness in the United States, Lyme disease. A family of proteins containing von Willebrand Factor A (VWFA) domains adjacent to a MoxR AAA+ ATPase have been found to be highly conserved in the genus Borrelia. Previously, a VWFA domain containing protein of B.

Proteomic composition of Nipah virus-like particles.

Unlabelled: Virions are often described as virus-only entities with no cellular components with the exception of the lipids in their membranes. However, advances in proteomics are revealing substantial amounts of host proteins in the viral particles. In the case of Nipah virus (NiV), the viral components in the virion have been known for some time.

The role of hydrophobic matching on transmembrane helix packing in cells.

Folding and packing of membrane proteins are highly influenced by the lipidic component of the membrane. Here, we explore how the hydrophobic mismatch (the difference between the hydrophobic span of a transmembrane protein region and the hydrophobic thickness of the lipid membrane around the protein) influences transmembrane helix packing in a cellular environment. Using a ToxRED assay in and a Bimolecular Fluorescent Complementation approach in human-derived cells complemented by atomistic molecular dynamics simulations we analyzed the dimerization of Glycophorin A derived transmembrane segments.

N-Linked Glycosylation of the p24 Family Protein p24δ5 Modulates Retrograde Golgi-to-ER Transport of K/HDEL Ligands in Arabidopsis.

The K/HDEL receptor ERD2 mediates the transport of soluble endoplasmic reticulum (ER)-resident proteins containing a C-terminal K/HDEL signal from the Golgi apparatus back to the ER via COPI (COat Protein I)-coated vesicles. Sorting of ERD2 within COPI vesicles is facilitated by p24 proteins. In Arabidopsis, p24δ5 has been shown to interact directly with ERD2 via its luminal GOLD (GOLgi Dynamics) domain and with COPI proteins via its cytoplasmic C-terminal tail at the acidic pH of the Golgi apparatus.

The C-terminal Domains of Apoptotic BH3-only Proteins Mediate Their Insertion into Distinct Biological Membranes.

Changes in the equilibrium of pro- and anti-apoptotic members of the B-cell lymphoma-2 (Bcl-2) protein family in the mitochondrial outer membrane (MOM) induce structural changes that commit cells to apoptosis. Bcl-2 homology-3 (BH3)-only proteins participate in this process by either activating pro-apoptotic effectors or inhibiting anti-apoptotic components and by promoting MOM permeabilization. The association of BH3-only proteins with MOMs is necessary for the activation and amplification of death signals; however, the nature of this association remains controversial, as these proteins lack a canonical transmembrane sequence.

The ER-Membrane Transport System Is Critical for Intercellular Trafficking of the NSm Movement Protein and Tomato Spotted Wilt Tospovirus.

Plant viruses move through plasmodesmata to infect new cells. The plant endoplasmic reticulum (ER) is interconnected among cells via the ER desmotubule in the plasmodesma across the cell wall, forming a continuous ER network throughout the entire plant. This ER continuity is unique to plants and has been postulated to serve as a platform for the intercellular trafficking of macromolecules.

Simple chemical tools to expand the range of proteomics applications.

Proteomics is an expanding technology with potential applications in many research fields. Even though many research groups do not have direct access to its main analytical technique, mass spectrometry, they can interact with proteomics core facilities to incorporate this technology into their projects. Protein identification is the analysis most frequently performed in core facilities and is, probably, the most robust procedure.

Redox modulation of Rubisco conformation and activity through its cysteine residues.

Treatment of purified Rubisco with agents that specifically oxidize cysteine-thiol groups causes catalytic inactivation and increased proteolytic sensitivity of the enzyme. It has been suggested that these redox properties may sustain a mechanism of regulating Rubisco activity and turnover during senescence or stress. Current research efforts are addressing the structural basis of the redox modulation of Rubisco and the identification of critical cysteines.