Mintz ereduetan toxina proteiko batekin egindako ikerketa espektroskopikoa

Lan honetan ACT toxinaren mutante batek, ACTΔN482, mintzean eskuratzen duen konformazioa aztertu da MC540 zunda erabiliz

Membrane Permeabilization by <i>Bordetella</i> Adenylate Cyclase Toxin Involves Pores of Tunable Size

RTX (Repeats in ToXin) pore-forming toxins constitute an expanding family of exoproteins secreted by many Gram-negative bacteria and involved in infectious diseases caused by said pathogens. Despite the relevance in the host/pathogen interactions, the structure and characteristics of the lesions formed by these toxins remain enigmatic. Here, we capture the first direct nanoscale pictures of lytic pores formed by an RTX toxin, the Adenylate cyclase (ACT), secreted by the whooping cough bacterium Bordetella pertussis. We reveal that ACT associates into growing-size oligomers of variable stoichiometry and heterogeneous architecture (lines, arcs, and rings) that pierce the membrane, and that, depending on the incubation time and the toxin concentration, evolve into large enough &#8220;holes&#8222; so as to allow the flux of large molecular mass solutes, while vesicle integrity is preserved. We also resolve ACT assemblies of similar variable stoichiometry in the cell membrane of permeabilized target macrophages, proving that our model system recapitulates the process of ACT permeabilization in natural membranes. Based on our data we propose a non-concerted monomer insertion and sequential mechanism of toroidal pore formation by ACT. A size-tunable pore adds a new regulatory element to ACT-mediated cytotoxicity, with different pore sizes being putatively involved in different physiological scenarios or cell types

Allosteric modulation of GSK-3β as a new therapeutic approach in limb girdle muscular dystrophy R1 calpain 3-related

18 p.-8 fig.-1 tab.Limb-girdle muscular dystrophy R1 calpain 3-related (LGMDR1) is an autosomal recessive muscular dystrophy produced by mutations in the CAPN3 gene. It is a rare disease and there is no cure or treatment for the disease while the pathophysiological mechanism by which the absence of calpain 3 provokes the dystrophy in muscles is not clear. However, key proteins implicated in Wnt and mTOR signaling pathways, which regulate muscle homeostasis, showed a considerable reduction in their expression and in their phosphorylation in LGMDR1 patients’ muscles. Finally, the administration of tideglusib and VP0.7, ATP non-competitive inhibitors of glycogen synthase kinase 3β (GSK-3β), restore the expression and phosphorylation of these proteins in LGMDR1 cells, opening the possibility of their use as therapeutic optionsThis work was financed through the grants received from the Health Research Fund (PI16/01325, PI17/01841 and DTS19/00061) of the Spanish Ministry of Economy and Competitiveness and the European Union (ERDF) and it was in part supported by the Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED: CB06/05/1126 to A.R., G.G., A.V., L.C.-F., A.L.d.M. and A.S. and CB18/05/00040 to A.M. and V.P.), Carlos III Health Institute and by GENE (Association of Neuromuscular diseases of Gipuzkoa). A.R. was supported by the predoctoral fellowship given by the department of Education, Universities and Research of the Basque Government (PRE-2016-1-0382).Peer reviewe