Selective inhibition of protein secretion by abrogating receptor-coat interactions during ER export.

Protein secretion is an essential process that drives cell growth, movement, and communication. Protein traffic within the secretory pathway occurs via transport intermediates that bud from one compartment and fuse with a downstream compartment to deliver their contents. Here, we explore the possibility that protein secretion can be selectively inhibited by perturbing protein-protein interactions that drive capture into transport vesicles.

A SURF4-to-proteoglycan relay mechanism that mediates the sorting and secretion of a tagged variant of sonic hedgehog.

SignificanceSonic Hedgehog (Shh) is a key signaling molecule that plays important roles in embryonic patterning, cell differentiation, and organ development. Although fundamentally important, the molecular mechanisms that regulate secretion of newly synthesized Shh are still unclear. Our study reveals a role for the cargo receptor, SURF4, in facilitating export of Shh from the endoplasmic reticulum (ER) via a ER export signal.

An in vitro vesicle formation assay reveals cargo clients and factors that mediate vesicular trafficking.

The fidelity of protein transport in the secretory pathway relies on the accurate sorting of proteins to their correct destinations. To deepen our understanding of the underlying molecular mechanisms, it is important to develop a robust approach to systematically reveal cargo proteins that depend on specific sorting machinery to be enriched into transport vesicles. Here, we used an in vitro assay that reconstitutes packaging of human cargo proteins into vesicles to quantify cargo capture.

Quantitative Profiling of N-linked Glycosylation Machinery in Yeast .

Asparagine-linked glycosylation is a common posttranslational protein modification regulating the structure, stability and function of many proteins. The -linked glycosylation machinery involves enzymes responsible for the assembly of the lipid-linked oligosaccharide (LLO), which is then transferred to the asparagine residues on the polypeptides by the enzyme oligosaccharyltransferase (OST). A major goal in the study of protein glycosylation is to establish quantitative methods for the analysis of site-specific extent of glycosylation.

Nanostructured monolinolein miniemulsions as delivery systems: Role of the internal mesophase on cytotoxicity and cell internalization.

Recent advances in nanoparticle systems for improved drug delivery display a great potential for the administration of active molecules. Here, lipid miniemulsions with various internal nanostructures were loaded with the chemotherapeutic agent Paclitaxel. The goal is to assess the impact of internal structures on their efficiency.

Protein degradation corrects for imbalanced subunit stoichiometry in OST complex assembly.

Protein degradation is essential for cellular homeostasis. We developed a sensitive approach to examining protein degradation rates in Saccharomyces cerevisiae by coupling a SILAC approach to selected reaction monitoring (SRM) mass spectrometry. Combined with genetic tools, this analysis made it possible to study the assembly of the oligosaccharyl transferase complex.

Molecular analysis of an alternative N-glycosylation machinery by functional transfer from Actinobacillus pleuropneumoniae to Escherichia coli.

N-Linked protein glycosylation is a frequent post-translational modification that can be found in all three domains of life. In a canonical, highly conserved pathway, an oligosaccharide is transferred by a membrane-bound oligosaccharyltransferase from a lipid donor to asparagines in the sequon NX(S/T) of secreted polypeptides. The δ-proteobacterium Actinobacillus pleuropneumoniae encodes an unusual pathway for N-linked protein glycosylation.

The novel [4,5-e][1,3]diazepine-4,8-dione and acyclic carbamoyl imino-ureido derivatives of imidazole: synthesis, anti-viral and anti-tumor Activity evaluations.

In the present paper, we report on the synthesis, and in vitro antiviral and cytostatic activities of a series of novel imidazole[4,5-e][1,3]diazepine-4,8-dione (compounds 9-11) and acyclic carbamoyl imino-ureido imidazole (compounds 12 and 13) derivatives. These new type of chemical entities showed no significant activity on the broad spectrum of DNA and RNA viruses. Results of antiproliferative assays performed on a panel of selected human tumor cell lines revealed that only compounds 1 and 5 showed moderate and selective cytostatic effect against HeLa cells (IC50 = 24 and 32 µM) with no concomitant cytotoxic effects on human normal fibroblasts (BJ).