Search results for "Macromolecular Substance"
showing 10 items of 882 documents
Controlling the semi-permeability of protein nanocapsules influences the cellular response to macromolecular payloads.
2021
Nanocapsules are an excellent platform for the delivery of macromolecular payloads such as proteins, nucleic acids or polyprodrugs, since they can both protect the sensitive cargo and target its delivery to the desired site of action. However, the release of macromolecules from nanocapsules remains a challenge due to their restricted diffusion through the nanoshell compared to small molecule cargo. Here, we designed degradable protein nanocapsules with varying crosslinking densities of the nanoshell to control the release of model macromolecules. While the crosslinking did not influence the degradability of the capsules by natural proteases, it significantly affected the release profiles. F…
Chaperone action in the posttranslational topological reorientation of the hepatitis B virus large envelope protein: Implications for translocational…
2003
The large L envelope protein of the hepatitis B virus utilizes a new folding pathway to acquire a dual transmembrane topology in the endoplasmic reticulum (ER). The process involves cotranslational membrane integration and subsequent posttranslational translocation of its preS subdomain into the ER. Here, we demonstrate that the conformational and functional heterogeneity of L depends on the action of molecular chaperones. Using coimmunoprecipitation, we observed specific interactions between L and the cytosolic Hsc70, in conjunction with Hsp40, and between L and the ER-resident BiP in mammalian cells. Complex formation between L and Hsc70 was abolished when preS translocation was artifici…
Influence of antibody binding on oxygen binding behavior of Panulirus interruptus hemocyanin
1997
Oxygen binding behavior of monomeric subunit a and the hexameric form of this subunit of hemocyanin of Panulirus interruptus is influenced by the binding of various monoclonal antibodies. These antibodies react with other surface parts of the subunit than its second domain in which the oxygen binding site is located. The influence of three monoclonal antibodies and their antigen binding fragments (F-ab) has been investigated. Two antibodies increase the oxygen affinity of monomeric hemocyanin from that observed in its low affinity T-state, while the third has little influence on this property. F-ab fragments abolish almost completely the cooperativity of oxygen binding by the hexameric hemo…
Molecular mass of macromolecules and subunits and the quaternary structure of hemoglobin from the microcrustacean Daphnia magna
2006
The molecular masses of macromolecules and subunits of the extracellular hemoglobin from the fresh-water crustacean Daphnia magna were determined by analytical ultracentrifugation, multiangle laser light scattering and electrospray ionization mass spectrometry. The hemoglobins from hypoxia-incubated, hemoglobin-rich and normoxia-incubated, hemoglobin-poor Daphnia magna were analyzed separately. The sedimentation coefficient of the macromolecule was 17.4 +/- 0.1 S, and its molecular mass was 583 kDa (hemoglobin-rich animals) determined by AUC and 590.4 +/- 11.1 kDa (hemoglobin-rich animals) and 597.5 +/- 49 kDa (hemoglobin-poor animals), respectively, determined by multiangle laser light sca…
Neutron Scattering Reveals Enhanced Protein Dynamics in Concanavalin A Amyloid Fibrils
2012
Protein aggregation is one of the most challenging topics in life sciences, and it is implicated in several human pathologies. The nature and the role of toxic species is highly debated, with amyloid fibrils being among the most relevant species for their peculiar structural and functional properties. Protein dynamics and in particular the ability to fluctuate through a large number of conformational substates are closely related to protein function. This Letter focuses on amyloid fibril dynamics, and, to our knowledge, it is the first neutron scattering study on a protein (Concanavalin A) isolated in its fibril state. Our results reveal enhanced atomic fluctuations in amyloid fibrils and i…
A Survey on Tubulin and Arginine Methyltransferase Families Sheds Light on
2019
Tubulins and microtubules (MTs) represent targets for taxane-based chemotherapy. To date, several lines of evidence suggest that effectiveness of compounds binding tubulin often relies on different post-translational modifications on tubulins. Among them, methylation was recently associated to drug resistance mechanisms impairing taxanes binding. The sea urchin is recognized as a research model in several fields including fertilization, embryo development and toxicology. To date, some α- and β-tubulin genes have been identified in P. lividus, while no data are available in echinoderms for arginine methyl transferases (PRMT). To evaluate the exploiting of the sea urchin embryo in the field o…
Plant protein phosphorylation monitored by capillary liquid chromatography–element mass spectrometry
2007
Abstract Many essential cellular functions such as growth rate, motility, and metabolic activity are linked to reversible protein phosphorylation, since they are controlled by signaling cascades based mainly on phosphorylation/dephosphorylation events. Quantification of global or site-specific protein phosphorylation is not straightforward with standard proteomic techniques. The coupling of capillary liquid chromatography (μLC) with ICP-MS (inductively coupled plasma-mass spectrometry) is a method which allows a quantitative screening of protein extracts for their phosphorus and sulfur content, and thus provides access to the protein phosphorylation degree. In extension of a recent pilot st…
SIK2 orchestrates actin-dependent host response upon Salmonella infection
2021
Significance Through conducting quantitative proteomics upon Salmonella infection, we identified a SIK2 signaling network, implementing the kinase into a so far concealed biological function. Our data exposed SIK2 as a central orchestrator of an actin regulatory network, coordinating the stability of Salmonella-containing vacuole (SCV) and cellular actin assembly, in order to limit the acute phase of the infection. Most strikingly, SIK2 is not exclusively acting locally on actin assembly associated with the SCV but impacts the actin cytoskeleton architecture in its entirety upon Salmonella infection. Our work provides a mechanistic framework for how the actin cytoskeleton is regulated and h…
B-Raf Acts via the ROCKII/LIMK/Cofilin Pathway To Maintain Actin Stress Fibers in Fibroblasts
2004
Members of the Raf family of serine/threonine protein kinases have been well studied in a variety of organisms ranging from Drosophila to humans. Three raf homologues (raf-1, B-raf, and A-raf) exist in mammals, while a single prototypic homologue exists in lower organisms. A wealth of genetic and biochemical data have indicated that Raf family members are signaling kinases that are integral components of the conserved Ras/Raf/MEK/ERK signaling cascade. Following activation by Ras-dependent mechanisms, Raf protein kinases act as mitogen-activated protein (MAP) kinase kinase kinases, which phosphorylate and activate the type 1/2 MAP kinase kinases, also known as MEK1/2. These dual-specificity…
Cardiovascular Events in Moderately to Severely Obese Obstructive Sleep Apnea Patients on Positive Airway Pressure Therapy.
2016
<b><i>Background:</i></b> In moderately to severely obese patients with obstructive sleep apnea (OSA), the effects of long-term positive airway pressure (PAP) treatment on cardiovascular risk are poorly defined. <b><i>Purpose:</i></b> To assess the effect of continuous positive airway pressure (CPAP) or noninvasive ventilation (NIV) on the occurrence of cardiovascular events in obese OSA patients. <b><i>Methods:</i></b> We performed a noninterventional observational study in obese OSA patients recruited between 2007 and 2010 at the Sleep Center, University of Grenoble, treated with CPAP or NIV, and followed for 5.6 year…