Mechanosensitive aquaporins.

Cellular systems must deal with mechanical forces to satisfy their physiological functions. In this context, proteins with mechanosensitive properties play a crucial role in sensing and responding to environmental changes. The discovery of aquaporins (AQPs) marked a significant breakthrough in the study of water transport.

Effect of TiO Nanoparticles and Extrusion Process on the Physicochemical Properties of Biodegradable and Active Cassava Starch Nanocomposites.

Biodegradable polymers have been strongly recognized as an alternative to replace traditional petrochemical plastics, which have become a global problem due to their long persistence in the environment. In this work, the effect of the addition of titanium dioxide nanoparticles (TiONP) on the morphology, physicochemical properties and biodegradation under industrial composting conditions of cassava starch-based nanocomposites obtained by extrusion at different screw speeds (80 and 120 rpm) were investigated. Films performed at 120 rpm (S and S-TiONP) showed completely processed starch and homogeneously distributed nanoparticles, leading to much more flexible nanocomposites than those obtained at 80 rpm.

Correlation of cellular traction forces and dissociation kinetics of adhesive protein zyxin revealed by multi-parametric live cell microscopy.

Cells exert traction forces on the extracellular matrix to which they are adhered through the formation of focal adhesions. Spatial-temporal regulation of traction forces is crucial in cell adhesion, migration, cellular division, and remodeling of the extracellular matrix. By cultivating cells on polyacrylamide hydrogels of different stiffness we were able to investigate the effects of substrate stiffness on the generation of cellular traction forces by Traction Force Microscopy (TFM), and characterize the molecular dynamics of the focal adhesion protein zyxin by Fluorescence Correlation Spectroscopy (FCS) and Fluorescence Recovery After Photobleaching (FRAP).

CMT-3 targets different α-synuclein aggregates mitigating their toxic and inflammogenic effects.

Parkinson's disease (PD) is a neurodegenerative disorder for which only symptomatic treatments are available. Repurposing drugs that target α-synuclein aggregation, considered one of the main drivers of PD progression, could accelerate the development of disease-modifying therapies. In this work, we focused on chemically modified tetracycline 3 (CMT-3), a derivative with reduced antibiotic activity that crosses the blood-brain barrier and is pharmacologically safe.

An adipose tissue galectin controls endothelial cell function via preferential recognition of 3-fucosylated glycans.

Upon overnutrition, adipocytes activate a homeostatic program to adjust anabolic pressure. An inflammatory response enables adipose tissue (AT) expansion with concomitant enlargement of its capillary network, and reduces energy storage by increasing insulin resistance. Galectin-12 (Gal-12), an endogenous lectin preferentially expressed in AT, plays a key role in adipocyte differentiation, lipolysis, and glucose homeostasis.

The effect of ionic strength and phosphate ions on the construction of redox polyelectrolyte-enzyme self-assemblies.

Layer by layer assembly of polyelectrolytes with proteins is a convenient tool for the development of functional biomaterials. Most of the studies presented in the literature are based on the electrostatic interaction between components of opposite charges, limiting the assembly possibilities. However, this process can be tuned by modifying the environment where the main constituents are dissolved.

A Patterned Butyl Methacrylate--2-Hydroxyethyl Acrylate Copolymer with Softening Surface and Swelling Capacity.

The tunable swelling and mechanical properties of nanostructures polymers are crucial parameters for the creation of adaptive devices to be used in diverse fields, such as drug delivery, nanomedicine, and tissue engineering. We present the use of anodic aluminum oxide templates as a nanoreactor to copolymerize butyl methacrylate and 2-hydroxyethyl acrylate under radical conditions. The copolymer obtained under confinement showed significant differences with respect to the same copolymer obtained in bulk conditions.

Continuous assembly of supramolecular polyamine-phosphate networks on surfaces: preparation and permeability properties of nanofilms.

Supramolecular self-assembly of molecular building blocks represents a powerful "nanoarchitectonic" tool to create new functional materials with molecular-level feature control. Here, we propose a simple method to create tunable phosphate/polyamine-based films on surfaces by successive assembly of poly(allylamine hydrochloride) (PAH)/phosphate anions (Pi) supramolecular networks. The growth of the films showed a great linearity and regularity with the number of steps.

Self-assembled phosphate-polyamine networks as biocompatible supramolecular platforms to modulate cell adhesion.

The modulation of cell adhesion via biologically inspired materials plays a key role in the development of realistic platforms to envisage not only mechanistic descriptions of many physiological and pathological processes but also new biointerfacial designs compatible with the requirements of biomedical devices. In this work, we show that the cell adhesion and proliferation of three different cell lines can be easily manipulated by using a novel biologically inspired supramolecular coating generated via dip coating of the working substrates in an aqueous solution of polyallylamine in the presence of phosphate anions-a simple one-step modification procedure. Our results reveal that selective cell adhesion can be controlled by varying the deposition time of the coating.

Live cell imaging reveals focal adhesions mechanoresponses in mammary epithelial cells under sustained equibiaxial stress.

Mechanical stimuli play a key role in many cell functions such as proliferation, differentiation and migration. In the mammary gland, mechanical signals such as the distension of mammary epithelial cells due to udder filling are proposed to be directly involved during lactation and involution. However, the evolution of focal adhesions -specialized multiprotein complexes that mechanically connect cells with the extracellular matrix- during the mammary gland development, as well as the influence of the mechanical stimuli involved, remains unclear.

Layer-by-Layer Assembled Microgels Can Combine Conflicting Properties: Switchable Stiffness and Wettability without Affecting Permeability.

Responsive interfacial architectures of practical interest commonly require the combination of conflicting properties in terms of their demand upon material structure. Switchable stiffness, wettability, and permeability, key features for tissue engineering applications, are in fact known to be exclusively interdependent. Here, we present a nanoarchitectonic approach that decouples these divergent properties by the use of thermoresponsive microgels as building blocks for the construction of three-dimensional arrays of interconnected pores.

Highly-organized stacked multilayers via layer-by-layer assembly of lipid-like surfactants and polyelectrolytes. Stratified supramolecular structures for (bio)electrochemical nanoarchitectonics.

Supramolecular self-assembly is of paramount importance for the development of novel functional materials with molecular-level feature control. In particular, the interest in creating well-defined stratified multilayers through simple methods using readily available building blocks is motivated by a multitude of research activities in the field of "nanoarchitectonics" as well as evolving technological applications. Herein, we report on the facile preparation and application of highly organized stacked multilayers via layer-by-layer assembly of lipid-like surfactants and polyelectrolytes.

Reversible modulation of the redox activity in conducting polymer nanofilms induced by hydrophobic collapse of a surface-grafted polyelectrolyte.

We present the covalent modification of a Pani-like conducting polymer (polyaminobenzylamine, PABA) by grafting of a polyelectrolyte brush (poly [2-(methacryloyloxy)-ethyl-trimethylammonium chloride], PMETAC). As PABA has extra pendant amino moieties, the grafting procedure does not affect the backbone nitrogen atoms that are implicated in the electronic structure of the conducting polymers. Moreover, perchlorate anions interact very strongly with the quaternary ammonium pendant groups of PMETAC through ion pairing.

Thermo-responsive PNIPAm nanopillars displaying amplified responsiveness through the incorporation of nanoparticles.

The possibility of combining more than one stimulus-responsive property into a single material holds interesting potential for the creation of adaptive devices to be used in diverse fields such as drug delivery, nanomedicine and tissue engineering. This paper describes a novel material based on thermo-responsive PNIPAm nanopillars with amplified surface properties through the incorporation of FeO nanoparticles. The incorporation of magnetic nanoparticles into the nanopillars, prepared via surface-initiated atom-transfer radical polymerization in anodized aluminum oxide templates, sharply increased their stiffness and hydrophobicity when increasing the temperature above the volume phase transition temperature.

Calcium dynamics in tomato pollen tubes using the Yellow Cameleon 3.6 sensor.

In vitro tomato pollen tubes show a cytoplasmic calcium gradient that oscillates with the same period as growth. Pollen tube growth requires coordination between the tip-focused cytoplasmic calcium concentration ([Ca]) gradient and the actin cytoskeleton. This [Ca] gradient is necessary for exocytosis of small vesicles, which contributes to the delivery of new membrane and cell wall at the pollen tube tip.

Two Arabidopsis late pollen transcripts are detected in cytoplasmic granules.

Many of mRNAs synthesized during pollen development are translated after germination, and we hypothesize that they are stored in cytoplasmic granules. We analyzed the cellular localization of the and Arabidopsis mRNAs, which are orthologues of the tobacco and tomato pollen mRNAs, respectively, by artificially labeling the transcripts with a MS2-GFP chimera. A MATLAB-automated image analysis helped to identify the presence of cytoplasmic and mRNA granules in mature pollen grains.

Thermally-induced softening of PNIPAm-based nanopillar arrays.

The surface properties of soft nanostructured hydrogels are crucial in the design of responsive materials that can be used as platforms to create adaptive devices. The lower critical solution temperature (LCST) of thermo-responsive hydrogels such as poly(N-isopropylacrylamide) (PNIPAm) can be modified by introducing a hydrophilic monomer to create a wide range of thermo-responsive micro-/nano-structures in a large temperature range. Using surface initiation atom-transfer radical polymerization in synthesized anodized aluminum oxide templates, we designed, fabricated, and characterized thermo-responsive nanopillars based on PNIPAm hydrogels with tunable mechanical properties by incorporating acrylamide monomers (AAm).

Monitoring in real-time focal adhesion protein dynamics in response to a discrete mechanical stimulus.

The adhesion of cells to the extracellular matrix is a hierarchical, force-dependent, multistage process that evolves at several temporal scales. An understanding of this complex process requires a precise measurement of forces and its correlation with protein responses in living cells. We present a method to quantitatively assess live cell responses to a local and specific mechanical stimulus.

High-Energy Dissipation Performance in Epoxy Coatings by the Synergistic Effect of Carbon Nanotube/Block Copolymer Conjugates.

Hierarchical assembly of hard/soft nanoparticles holds great potential as reinforcements for polymer nanocomposites with tailored properties. Here, we present a facile strategy to integrate polystyrene-grafted carbon nanotubes (PSgCNT) (0.05-0.

Loop B serine of a plasma membrane aquaporin type PIP2 but not PIP1 plays a key role in pH sensing.

In the plant kingdom, the plasma membrane intrinsic aquaporins (PIPs) constitute a highly conserved group of water channels with the capacity of rapidly adjusting the water permeability (P) of a cell by a gating response. Most evidence regarding this mechanism was obtained by different biophysical approaches including the crystallization of a Spinaca olaracea PIP2 aquaporin (SoPIP2;1) in an open and close conformation. A close state seems to prevail under certain stimuli such as cytosolic pH decrease, intracellular Ca concentration increase and dephosphorylation of specific serines.

PIP Water Transport and Its pH Dependence Are Regulated by Tetramer Stoichiometry.

Many plasma membrane channels form oligomeric assemblies, and heterooligomerization has been described as a distinctive feature of some protein families. In the particular case of plant plasma membrane aquaporins (PIPs), PIP1 and PIP2 monomers interact to form heterotetramers. However, the biological properties of the different heterotetrameric configurations formed by PIP1 and PIP2 subunits have not been addressed yet.

Alternative Splicing of G9a Regulates Neuronal Differentiation.

Chromatin modifications are critical for the establishment and maintenance of differentiation programs. G9a, the enzyme responsible for histone H3 lysine 9 dimethylation in mammalian euchromatin, exists as two isoforms with differential inclusion of exon 10 (E10) through alternative splicing. We find that the G9a methyltransferase is required for differentiation of the mouse neuronal cell line N2a and that E10 inclusion increases during neuronal differentiation of cultured cells, as well as in the developing mouse brain.

Rab27a controls HIV-1 assembly by regulating plasma membrane levels of phosphatidylinositol 4,5-bisphosphate.

During the late stages of the HIV-1 replication cycle, the viral polyprotein Pr55(Gag) is recruited to the plasma membrane (PM), where it binds phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and directs HIV-1 assembly. We show that Rab27a controls the trafficking of late endosomes carrying phosphatidylinositol 4-kinase type 2 α (PI4KIIα) toward the PM of CD4(+) T cells. Hence, Rab27a promotes high levels of PM phosphatidylinositol 4-phosphate and the localized production of PI(4,5)P2, therefore controlling Pr55(Gag) membrane association.