Sabina Maté
National Scientific and Technical Research Council
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Sabina Maté.
Journal of Biological Chemistry | 2009
Vanesa Herlax; Sabina Maté; Omar Rimoldi; Laura Bakás
α-Hemolysin (HlyA) is an exotoxin secreted by some pathogenic strains of Escherichia coli that causes lysis of several mammalian cells, including erythrocytes of different species. HlyA is synthesized as a protoxin, pro-HlyA, which is activated by acylation at two internal lysines Lys-563 and Lys-689. It has been proposed that pore formation is the mechanism of cytolytic activity for this toxin, as shown in experiments with whole cells, planar lipid membranes, and liposomes, but these experiments have yielded conflicting results about the structure of the pore. In this study, HlyA cysteine replacement mutant proteins of amino acids have been labeled with Alexa-488 and Alexa-546. Fluorescence resonance energy transfer measurements, employing labeled toxin bound to sheep ghost erythrocytes, have demonstrated that HlyA oligomerizes on erythrocyte membranes. As the cytotoxic activity is absolutely dependent on acylation, we have studied the role of acylation in the oligomerization, demonstrating that fatty acids are essential in this process. On the other hand, fluorescence resonance energy transfer and the hemolytic activity decrease when the erythrocyte ghosts are cholesterol-depleted, hence indicating the role of membrane microdomains in the clustering of HlyA. Simultaneously, HlyA was found in detergent-resistant membranes. Pro-HlyA has also been found in detergent-resistant membranes, thus demonstrating that the importance of acyl chains in toxin oligomerization is the promotion of protein-protein interaction. These results change the concept of the main role assigned to acyl chain in the targeting of proteins to membrane microdomains.
Lipids | 2007
Sabina Maté; Juan Pablo Layerenza; Ana Ves-Losada
The incorporation of exogenous fatty acids bound to L-FABP into nuclei was studied. Rat liver cell nuclei and nuclear matrices (membrane depleted nuclei) were incubated in vitro with [1-14C]18:0 and 20:4n-6 either free or bound to L-FABP, ATP and CoA. FA esterification in whole nuclei and endonuclear lipids was ATP-CoA-dependent, and with specificity regarding fatty acid type and lipid class. 18:0 and 20:4n-6, free or L-FABP bound, showed the same incorporation and esterification pattern in lipids of whole nuclei. Only 20:4n-6 L-FABP bound was less incorporated into TAG with respect to free 20:4n-6. In the nuclear matrix, 18:0 free or L-FABP bound was esterified with a higher specific activity (SA) into: PtdEtn > PtdIns, PtdSer > PtdCho. 20:4n-6 free or L-FABP bound was esterified into: PtdIns > PtdEtn > PtdCho. 20:4n-6:L-FABP was esterified in endonuclear total-PL and PtdIns with a greater SA with respect to free 20:4n-6 and with a minor one as FFA. To summarize, trafficking of FA to nuclei includes esterification of 18:0 and 20:4n-6 either free or L-FABP-bound, into nuclear and endonuclear lipids by an ATP-CoA-dependent pathway. Endonuclear fatty acid esterification was more active than that in whole nuclei, and independent of the nuclear membrane. Esterification patterns of fatty acids L-FABP-bound or free into whole nuclear lipids were the same whereas in the nuclear matrix, L-FABP could play an important role in the mobilization of 20:4n-6 into specific sites of utilization such as the PtdIns pools.
Colloids and Surfaces B: Biointerfaces | 2019
Romina Vazquez; M. Antonieta Daza Millone; Felippe J. Pavinatto; Maria Laura Fanani; Osvaldo N. Oliveira; M. E. Vela; Sabina Maté
Membrane structure is a key factor for the cell`s physiology, pathology, and therapy. Evaluating the importance of lipid species such as N-nervonoyl sphingomyelin (24:1-SM) -able to prevent phase separation- to membrane structuring remains a formidable challenge. This is the first report in which polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS) is applied to investigate the lipid-lipid interactions in 16:0 vs 24:1-SM monolayers and their mixtures with 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol (Chol) (DOPC/SM/Chol 2:1:1). From the results we inferred that the cis double bond (Δ15) in 24:1-SM molecule diminishes intermolecular H-bonding and chain packing density compared to that of 16:0-SM. In ternary mixtures containing 16:0-SM, the relative intensity of the two components of the Amide I band reflected changes in the H-bonding network due to SM-Chol interactions. In contrast, the contribution of the main components of the Amide I band in DOPC/24:1-SM/Chol remained as in 24:1-SM monolayers, with a larger contribution of the non-H-bonded component. The most interesting feature in these ternary films is that the CO stretching mode of DOPC appeared with an intensity similar to that of SM Amide I band in DOPC/16:0-SM/Chol monolayers (a two-phase [Lo/Le] system), whereas an extremely low intensity of the CO band was detected in DOPC/24:1-SM/Chol monolayers (single Le phase). This is evidence that the unsaturation in 24:1-SM affected not only the conformational properties of acyl chains but also the orientation of the chemical groups at the air/water interface. The physical properties and overall H-bonding ability conferred by 24:1-SM may have implications in cell signaling and binding of biomolecules.
Biophysical Journal | 2018
Carlos Muñoz-Garay; Sathishkumar Munusamy; Agustin Luna Bulbarela; Romina Vazquez; Vanesa Herlax; Sabina Maté; Leobardo Serrano Carreon
Tercera Época | 2017
Karen Strack; Sabina Maté; Vanesa Herlax
Tercera Época | 2017
Lucía Cané; Fanny Guzmán; Sabina Maté; Vanesa Herlax
Biophysical Journal | 2017
Sabina Maté; Romina Vazquez; Felippe J. Pavinatto; M. Antonieta Daza-Millone; Vanesa Herlax; Laura S. Bakás; Osvaldo N. Oliveira; M. E. Vela
Biochemical Journal | 2017
Cora Lilia Alvarez; Gerardo R. Corradi; Natalia Lauri; Irene Marginedas-Freixa; María Florencia Leal Denis; Nicolás Enrique; Sabina Maté; Verónica Milesi; Mariano Anibal Ostuni; Vanesa Herlax; Pablo J. Schwarzbaum
Tercera Época | 2016
Joshua Godoy Coto; Maite Zavala; Ana María Bernasconi; Vanesa Herlax; M. Celeste Villa Abrille; Sabina Maté
Tercera Época | 2016
Romina Vazquez; María Antonieta Daza Millone; M. E. Vela; Laura Bakás; Vanesa Herlax; Sabina Maté