21 documents found, page 1 of 3
Characterization and Vaccine Potential of Outer Membrane Vesicles from Photobac...
Teixeira, A; Loureiro, I; Lisboa, J; Oliveira, PN; Azevedo, JE; dos Santos, NMS; do Vale, APhotobacterium damselae subsp. piscicida (Phdp) is a Gram-negative fish pathogen with worldwide distribution and broad host specificity that causes heavy economic losses in aquaculture. Although Phdp was first identified more than 50 years ago, its pathogenicity mechanisms are not completely understood. In this work, we report that Phdp secretes large amounts of outer membrane vesicles (OMVs) when cultured in v...
Unconventional structure and mechanisms for membrane interaction and translocat...
Lisboa, J; Pereira, C; Pinto, RD; Rodrigues, IS; Pereira, LMG; Pinheiro, B; Oliveira, P; Pereira, PJB; Azevedo, JE; Durand, D; Benz, R; do Vale, ABacterial AB toxins are secreted key virulence factors that are internalized by target cells through receptor-mediated endocytosis, translocating their enzymatic domain to the cytosol from endosomes (short-trip) or the endoplasmic reticulum (long-trip). To accomplish this, bacterial AB toxins evolved a multidomain structure organized into either a single polypeptide chain or non-covalently associated polypeptid...
A mechanistic perspective on pex1 and pex6, two aaa+ proteins of the peroxisoma...
Pedrosa, AG; Francisco, T; Ferreira, MJ; Rodrigues, TA; Barros-Barbosa, A; Azevedo, JEIn contrast to many protein translocases that use ATP or GTP hydrolysis as the driving force to transport proteins across biological membranes, the peroxisomal matrix protein import machinery relies on a regulated self-assembly mechanism for this purpose and uses ATP hydrolysis only to reset its components. The ATP-dependent protein complex in charge of resetting this machinery—the Receptor Export Module (REM)—...
Peroxisomal monoubiquitinated PEX5 interacts with the AAA ATPases PEX1 and PEX6...
Pedrosa, AG; Francisco, T; Bicho, D; Dias, AF; Barros-Barbosa, A; Hagmann, V; Dodt, G; Rodrigues, TA; Azevedo, JEPEX1 and PEX6 are two members of the ATPases associated with diverse cellular activities (AAA) family and the core components of the receptor export module of the peroxisomal matrix protein import machinery. Their role is to extract monoubiquitinated PEX5, the peroxisomal protein-shuttling receptor, from the peroxisomal membrane docking/translocation module (DTM), so that a new cycle of protein transportation c...
Chemically monoubiquitinated PEX5 binds to the components of the peroxisomal do...
Hagmann, V; Sommer, S; Fabian, P; Bierlmeier, J; van Treel, N; Mootz, H; Schwarzer, D; Azevedo, JE; Dodt, GPeroxisomal matrix proteins contain either a peroxisomal targeting sequence 1 (PTS1) or a PTS2 that are recognized by the import receptors PEX5 and PEX7, respectively. PEX5 transports the PTS1 proteins and the PEX7/PTS2 complex to the docking translocation module (DTM) at the peroxisomal membrane. After cargo release PEX5 is monoubiquitinated and extracted from the peroxisomal membrane by the receptor export ma...
Arabidopsis thaliana SPF1 and SPF2 are nuclear-located ULP2-like SUMO proteases...
Castro, P; Santos, M; Freitas, S; Cana-Quijada, P; Lourenço, T; Rodrigues, M; Fonseca, F; Ruiz-Albert, J; Azevedo, JE; Tavares, R; Castillo, APost-translational modifiers such as the small ubiquitin-like modifier (SUMO) peptide act as fast and reversible protein regulators. Functional characterization of the sumoylation machinery has determined the key regulatory role that SUMO plays in plant development. Unlike components of the SUMO conjugation pathway, SUMO proteases (ULPs) are encoded by a relatively large gene family and are potential sources of...
Determining the topology of peroxisomal proteins using protease protection assays
Francisco, T; Dias, AF; Pedrosa, AG; Grou, CP; Rodrigues, TA; Azevedo, JEProtease protection assays are powerful tools to determine the topology of organelle proteins. Their simplicity, together with the fact that they are particularly suited to characterize endogenous proteins, are their major advantages and the reason why these assays have been in use for so many years. Here, we provide a detailed protocol to use with mammalian peroxisomes. Suggestions on how these assays can be c...
Protein transport into peroxisomes: Knowns and unknowns
Francisco, T; Rodrigues, TA; Dias, AF; Barros-Barbosa, A; Bicho, D; Azevedo, JEPeroxisomal matrix proteins are synthesized on cytosolic ribosomes and rapidly transported into the organelle by a complex machinery. The data gathered in recent years suggest that this machinery operates through a syringe-like mechanism, in which the shuttling receptor PEX5 - the “plunger” - pushes a newly synthesized protein all the way through a peroxisomal transmembrane protein complex - the “barrel” - into...
The peroxisomal matrix protein translocon is a large cavity-forming protein ass...
Dias, AF; Rodrigues, TA; Pedrosa, AG; Barros-Barbosa, A; Francisco, T; Azevedo, JEA remarkable property of the machinery for import of peroxisomal matrix proteins is that it can accept already folded proteins as substrates. This import involves binding of newly synthesized proteins by cytosolic peroxisomal biogenesis factor 5 (PEX5) followed by insertion of the PEX5– cargo complex into the peroxisomal membrane at the docking/translocation module (DTM). However, how these processes occur rema...
Evaluation of the activity and substrate specificity of the human SENP family o...
Mendes, A; Grou, CP; Azevedo, JE; Pinto, MPProtein modification with the small ubiquitin-like modifier (SUMO) is a reversible process regulating many central biological pathways. The reversibility of SUMOylation is ensured by SUMO proteases many of which belong to the sentrin/SUMO-specific protease (SENP) family. In recent years, many advances have been made in allocating SENPs to specific biological pathways. However, due to difficulties in obtaining r...