Alex Perálvarez-Marín

Autonomous University of Barcelona | UAB · Department of Biochemistry and Molecular Biology

Transient potential receptor vanilloid 2 (TRPV2) is widely expressed through the nervous system and specifically found in neuronal subpopulations and some glial cells. TRPV2 is known to be sensitized by methionine oxidation, which results from inflammation. Here we aim to characterize the expression and regulation of TRPV2 in myelination pathologie...

Dynorphins are endogenous neuropeptides that function as ligands for the κ-opioid receptor. In addition to opioid activity, dynorphins can induce several pathological effects such as neurological dysfunctions and cell death. Previous studies have suggested that Dynorphin A (DynA) mediates some pathogenic actions through formation of transient pores...

Mycoplasmas are parasitic bacteria with streamlined genomes and complex nutritional requirements. Although iron is vital for almost all organisms, its utilization by mycoplasmas is controversial. Despite its minimalist nature, mycoplasmas can survive and persist within the host, where iron availability is rigorously restricted through nutritional i...

Physiological aging is characterized by an imbalance of pro-inflammatory and anti-inflammatory mediators leading to neuroinflammation. Microglial cells, which are highly regulated by the local microenvironment, undergo specific changes depending upon the brain area during aging. The aim of this study was to evaluate the influence of age over microg...

Gene targeting approaches have recently demonstrated the essential role for the malaria parasite of membrane transport proteins involved in lipid transport and in the maintenance of membrane lipid asymmetry, representing emerging oportunites for therapeutical intervention. This is the case of ATP2, a Plasmodium-encoded 4 P-type ATPase (P4-ATPase or...

Myotonic Dystrophy type 1 (DM1) is an incurable neuromuscular disorder caused by toxic DMPK transcripts that carry CUG repeat expansions in the 3′ untranslated region (3′UTR). The intrinsic complexity and lack of crystallographic data makes noncoding RNA regions challenging targets to study in the field of drug discovery. In DM1, toxic transcripts...

Fourier Transform Infrared microspectroscopy (μFTIR) is a very useful method to analyze the biochemical properties of biological samples in situ. Many diseases affecting the central nervous system (CNS) have been studied using this method, to elucidate alterations in lipid oxidation or protein aggregation, among others. In this work, we describe in...

Efficient mechanisms of lipid transport are indispensable for the Plasmodium malaria parasite along the different stages of its intracellular life-cycle. Gene targeting approaches have recently revealed the irreplaceable role of the Plasmodium-encoded type 4 P-type ATPases (P4-ATPases or lipid flippases), ATP2, together with its potential involveme...

Transition metals participate in numerous enzymatic reactions and they are essential for survival in all living organisms. For this reason, bacterial pathogens have evolved dedicated machineries to effectively compete with their hosts and scavenge metals at the site of infection. In this study, we investigated the mechanisms controlling metal acqui...

Transient receptor potential cation channels are emerging as important physiological and therapeutic targets. Within the vanilloid subfamily, transient receptor potential vanilloid 2 (TRPV2) and 4 (TRPV4) are osmo- and mechanosensors becoming critical determinants in cell structure and activity. However, knowledge is scarce regarding how TRPV2 and...

Alzheimer's disease (AD) is a neurodegenerative process characterized by the accumulation of extracellular deposits of amyloid β-peptide (Aβ), which induces neuronal death. Monomeric Aβ is not toxic but tends to aggregate into β-sheets that are neurotoxic. Therefore to prevent or delay AD onset and progression one of the main therapeutic approaches...

Bioinformatics is a very resourceful tool to understand evolution of membrane proteins, such as transient receptor potential channels. Expert bioinformatics users rely on specialized scripting and programming skills. Several web servers and standalone tools are available for nonadvanced users willing to develop projects to understand their system o...

Novel strategies in the design of HIV-1 fusion/entry inhibitors are based on the construction of dual-targeting fusion proteins and peptides with synergistic antiviral effects. In this work we describe the design of dual-targeting peptides composed of peptide domains of E2 and E1 envelope proteins from Human Pegivirus with the aim of targeting both...

Constitutive or regulated membrane protein trafficking is a key cell biology process. Transient receptor potential channels are somatosensory proteins in charge of detecting several physical and chemical stimuli, thus requiring fine vesicular trafficking. The membrane proximal or pre-S1 domain (MPD) is a highly conserved domain in transient recepto...

Heterologous expression of human membrane proteins is a challenge in structural biology towards drug discovery. Here we report a complete expression and purification process of a functional human sodium/D-glucose co-transporter 1 (hSGLT1) in Pichia pastoris as representative example of a useful strategy for any human membrane protein. hSGLT1 gene w...

Ion channels are well placed to transduce environmental cues into signals used by cells to generate a wide range of responses, but little is known about their role in the regulation of RNA metabolism. Here we show that the TRPV4 cation channel binds the DEAD-box RNA helicase DDX3X and regulates its function. TRPV4-mediated Ca2+ influx releases DDX3...

Proteomics aids to the discovery and expansion of protein-protein interaction networks, which are key to understand molecular mechanisms in physiology and physiopathology, but also to infer protein function in a guilt-by-association fashion. In this study we use a systematic protein-protein interaction membrane yeast twohybrid method to expand the...

TRPV4 cation channel activation by cytochrome P450-mediated derivatives of arachidonic acid (AA), epoxyeicosatrienoic acids (EETs), constitute a major mechanisms of endothelium-derived vasodilatation. Besides, TRPV4 mechano/osmosensitivity depends on phospholipase A2 (PLA2) activation and subsequent production of AA and EETs. However, the lack of e...

The amyloid beta-peptide (Aβ) plays a leading role in Alzheimer's disease (AD) physiopathology. Even though monomeric forms of Aβ are harmless to cells, Aβ can aggregate into β-sheet oligomers and fibrils, which are both neurotoxic. Therefore, one of the main therapeutic approaches to cure or delay AD onset and progression is targeting Aβ aggregati...

Significance statement: We report that nitration (i.e., the irreversible addition of a nitro group) of the Alzheimer-related peptide amyloid-β (Aβ) favors the stabilization of highly toxic oligomers and inhibits the formation of Aβ fibrils. The nitrated Aβ oligomers are more toxic to neurons due to increased cytosolic calcium levels throughout the...

Molecular dynamics simulations have been used to study the alternate access mechanism of the melibiose transporter from Escherichia coli. Starting from the outward-facing partially occluded form, 2 out of 12 simulations produced an outward full open form and one partially open, whereas the rest yielded fully or partially occluded forms. The shape o...

The variety of nanoparticles (NPs) used in biological applications is increasing and their interaction with biological media is becoming more important. Proteins are commonly the first biomolecules that NPs encounter when they interact with biological systems either in vitro or in vivo. Commonly those proteins adsorb quickly onto the NPs? surface,...

The knowledge of three-dimensional structures at atomic resolution of membrane transport proteins has improved considerably our understanding of their physiological roles and pathological implications. However, most structural biology techniques require an optimal candidate within a protein family for structural determination with (a) reasonable pr...

Optogenetics, the pushing field of research that uses light-switchable biochemical tools in a sophisticated technological approach for monitoring or controlling neural function, is rapidly evolving with the discovery and development of novel microbial rhodopsins. Light absorbing membrane proteins, as tools for brain research, are promoting new appl...

A mortality rate higher than 90 % was observed in a larva-rearing facility for Pacific cod, Gadus macrocephalus, in China. Larvae showing clinical signs of infection were collected. Initial suspicion of nervous necrosis virus (NNV) infection was confirmed by sequencing, absolute quantification real-time PCR (A-qPCR), and electron microscopy. The nu...

Mortality (>90%) is a big concern in larval rearing facilities of Pacific cod, Gadus macrocephalus, limiting its culture presently still in the experimental stages. Understanding the immune system development of G. macrocephalus is crucial to optimize the aquaculture of this species, to improve the use of economic resources and to avoid abuse of an...

The transient receptor potential vanilloid family includes four ion channels-TRPV1, TRPV2, TRPV3 and TRPV4-that are represented within the vertebrate subphylum and involved in several sensory and physiological processes. These channels are related to adaptation to the environment, and probably under strong evolutionary pressure. Using multiple sequ...

Innate immunity plays a key role against the nervous necrosis virus (NNV) before adaptive immunity kicks off during fish development. We have studied the interferon-inducible Mx and the antimicrobial peptide hepcidin genes to probe the status of innate immunity in red-spotted grouper, Epinephelus akaara larvae and juveniles. For this study we exami...

Transient receptor potential (TRP) ion channels are emerging as a new set of membrane proteins involved in a vast array of cellular processes and regulated by a large number of physical and chemical stimuli, which involves them with sensory cell physiology. The vanilloid TRP subfamily (TRPV) named after the vanilloid receptor 1 (TRPV1) consists of...

Bacteriorhodopsin has a polar cluster of amino acids surrounding the retinal molecule, which is responsible for light harvesting to fuel proton pumping. From our previous studies, we have shown that threonine 90 is the pivotal amino acid in this polar cluster, both functionally and structurally. In an attempt to perform a phenotype rescue, we have...

Retinal isomer composition analysis. HPLC of Dark and light adapted (DA and LA) T90A (black lines) and WT (grey lines) showing there is not light adaptation for the mutant. (TIF)

Dark-light adaptation. Difference spectra between the light and the dark-adapted form of a 10 µM suspension of the four chromoproteins in 50 mM phosphate buffer. The suspensions have been kept in dark conditions for more than a month and a spectrum of each protein was acquired. Afterwards the suspension was illuminated for one minute at maximum int...

Methods for the retinal analog synthesis and the HPLC procedures. (PDF)

Dark-light adaptation. Dark-light adaptation of the four chromoproteins at 10 µM in 50 mM phosphate buffer at pH 6.5. The differences in scattering are due to the aggregation during the time of dark adaptation (more than one month). (TIF)

TRPV2 is a member of the superfamily of the Transient Receptor Potential (TRP) ion channels. These channels are assembled into homotetramers and allow cations across the membrane in response to physico-chemical stimuli such as heat, pressure, osmotic changes, etc. TRPV2 is an orphan receptor, since no specific endogenous ligand has been identified...

Complete set of identified RyR1 single-particles incubated with anti-SPRY2 antibodies presenting additional mass (indicated by white arrows). Unprocessed RyR1 particles incubated with the specified anti-SPRY2 antibody (anti-SPRY2-A, anti-SPRY2-B, anti-SPRY2-C; upper row), and calculated 2D projections (bottom row) for RyR1 containing four 30 Å radi...

The type 1 skeletal muscle ryanodine receptor (RyR1) is principally responsible for Ca(2+) release from the sarcoplasmic reticulum and for the subsequent muscle contraction. The RyR1 contains three SPRY domains. SPRY domains are generally known to mediate protein-protein interactions, however the location of the three SPRY domains in the 3D structu...

Reaction-induced infrared difference spectroscopy is a sensitive method to detect absorbance changes that accompany biomolecular Reaction-induced infrared difference spectroscopy is a sensitive method to detect absorbance changes that accompany biomolecular reactions, even if they are very small. One of the ways to trigger reactions in the infrared...

IntroductionSolubilization of IMPsIMP PurificationCharacterization of Solubilized IMPsAppendixAcknowledgmentsAbbreviationsReferences

We have performed a quantitative X-ray absorption fine structure analysis of bacteriorhodopsin in purple membrane patches and in lipidic cubic phases regenerated with Mn(2+). Lipidic cubic phases and purple membrane results have been compared, demonstrating that the lipidic cubic phase process does not introduce relevant distortions in the local ge...

Detergent-mediated reconstitution of bacteriorhodopsin (BR) into large unilamellar vesicles (LUVs) was investigated, and the effects were carefully characterized for every step of the procedure. LUVs were prepared by the extrusion method, and their size and stability were examined by dynamic light scattering. BR was incorporated into the LUVs using...

The formation and structure of proinsulin C-peptide oligomers has been investigated by PAGE, NMR spectroscopy and dynamic light scattering. The results obtained show that C-peptide forms oligomers of different sizes, and that their formation and size distribution is altered by salt and divalent metal ions, which indicates that the aggregation proce...

FireDock Clustering. Clustering of the ten lowest energy solutions ranked by FireDock for ApoE2 (A, docking energies ranging from −64.52 to −45.22 Kcal/mol); ApoE3 (B, docking energies ranging from −62.70 to −48.30 Kcal/mol); and ApoE4 (C, docking energies ranging from −60.94 to −45.43 Kcal/mol). The lowest energy solution for Aβ is represented as...

The relationship between Apolipoprotein E (ApoE) and the aggregation processes of the amyloid beta (A beta) peptide has been shown to be crucial for Alzheimer's disease (AD). The presence of the ApoE4 isoform is considered to be a contributing risk factor for AD. However, the detailed molecular properties of ApoE4 interacting with the A beta peptid...

The relationship between Apolipoprotein E (ApoE) and the aggregation processes of the amyloid β (Aβ) peptide has been shown to be crucial for Alzheimer's disease (AD). ApoE4 is considered as a contributing risk factor for AD. Although various mechanisms have been proposed to explain the physiological and pathological role of this relationship, the...

A flashy protein: The flash-induced transient protonation of pyranine has been studied in the presence of the cross-linked double mutant E166C/A228C (red trace), a reduced mutant (blue trace), and wildtype bacteriorhodopsin (gray traces). If helices F and C are cross-linked, there is a delay in both proton release (extracellular side) and proton up...

Several biophysical techniques have been used to determine differences in the aggregation profile (i.e., the secondary structure, aggregation propensity, dynamics, and morphology of amyloid structures) and the effects on cell viability of three variants of the amyloid beta peptide involved in Alzheimer's disease. We focused our study on the Glu22 r...