Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
Autophagy ; 19(11): 3017-3018, 2023 11.
Article in English | MEDLINE | ID: mdl-37415304

ABSTRACT

ABBREVIATIONS: Autophagy-related 9 (Atg9); cytoplasm-to-vacuole targeting (Cvt); Golgi-associated retrograde protein (GARP); multisubunit tethering complexes (MTCs); phagophore assembly site (PAS); phosphatidylserine (PS); Protein interactions from Imaging Complexes after Translocation (PICT); transport protein particle III (TRAPPIII); type IV P-type ATPases (P4-ATPases).


Subject(s)
Saccharomyces cerevisiae Proteins , Vesicular Transport Proteins , Autophagy , Autophagy-Related Proteins/metabolism , Cold Temperature , Protein Transport , Saccharomyces cerevisiae Proteins/metabolism , Transport Vesicles/metabolism , Vesicular Transport Proteins/metabolism
2.
EMBO Rep ; 24(5): e56134, 2023 05 04.
Article in English | MEDLINE | ID: mdl-36929574

ABSTRACT

Multisubunit Tethering Complexes (MTCs) are a set of conserved protein complexes that tether vesicles at the acceptor membrane. Interactions with other components of the trafficking machinery regulate MTCs through mechanisms that are partially understood. Here, we systematically investigate the interactome that regulates MTCs. We report that P4-ATPases, a family of lipid flippases, interact with MTCs that participate in the anterograde and retrograde transport at the Golgi, such as TRAPPIII. We use the P4-ATPase Drs2 as a paradigm to investigate the mechanism and biological relevance of this interplay during transport of Atg9 vesicles. Binding of Trs85, the sole-specific subunit of TRAPPIII, to the N-terminal tail of Drs2 stabilizes TRAPPIII on membranes loaded with Atg9 and is required for Atg9 delivery during selective autophagy, a role that is independent of P4-ATPase canonical functions. This mechanism requires a conserved I(S/R)TTK motif that also mediates the interaction of the P4-ATPases Dnf1 and Dnf2 with MTCs, suggesting a broader role of P4-ATPases in MTC regulation.


Subject(s)
Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Adenosine Triphosphatases/genetics , Adenosine Triphosphatases/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Autophagy-Related Proteins/genetics , Autophagy-Related Proteins/metabolism , Membrane Proteins/genetics , Membrane Proteins/metabolism , Calcium-Transporting ATPases/chemistry , Calcium-Transporting ATPases/metabolism , ATP-Binding Cassette Transporters/metabolism
3.
Elife ; 62017 03 06.
Article in English | MEDLINE | ID: mdl-28262097

ABSTRACT

Cell growth requires synthesis of ribosomal RNA by RNA polymerase I (Pol I). Binding of initiation factor Rrn3 activates Pol I, fostering recruitment to ribosomal DNA promoters. This fundamental process must be precisely regulated to satisfy cell needs at any time. We present in vivo evidence that, when growth is arrested by nutrient deprivation, cells induce rapid clearance of Pol I-Rrn3 complexes, followed by the assembly of inactive Pol I homodimers. This dual repressive mechanism reverts upon nutrient addition, thus restoring cell growth. Moreover, Pol I dimers also form after inhibition of either ribosome biogenesis or protein synthesis. Our mutational analysis, based on the electron cryomicroscopy structures of monomeric Pol I alone and in complex with Rrn3, underscores the central role of subunits A43 and A14 in the regulation of differential Pol I complexes assembly and subsequent promoter association.


Subject(s)
DNA, Ribosomal/genetics , Pol1 Transcription Initiation Complex Proteins/metabolism , Protein Multimerization , RNA Polymerase I/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/enzymology , Transcription, Genetic , Cryoelectron Microscopy , DNA Mutational Analysis , Protein Binding , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism
4.
Cell ; 168(3): 400-412.e18, 2017 01 26.
Article in English | MEDLINE | ID: mdl-28129539

ABSTRACT

The structural characterization of protein complexes in their native environment is challenging but crucial for understanding the mechanisms that mediate cellular processes. We developed an integrative approach to reconstruct the 3D architecture of protein complexes in vivo. We applied this approach to the exocyst, a hetero-octameric complex of unknown structure that is thought to tether secretory vesicles during exocytosis with a poorly understood mechanism. We engineered yeast cells to anchor the exocyst on defined landmarks and determined the position of its subunit termini at nanometer precision using fluorescence microscopy. We then integrated these positions with the structural properties of the subunits to reconstruct the exocyst together with a vesicle bound to it. The exocyst has an open hand conformation made of rod-shaped subunits that are interlaced in the core. The exocyst architecture explains how the complex can tether secretory vesicles, placing them in direct contact with the plasma membrane.


Subject(s)
Exocytosis , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/metabolism , Golgi Apparatus/metabolism , Models, Molecular , Secretory Vesicles/metabolism
5.
PLoS One ; 10(3): e0119707, 2015.
Article in English | MEDLINE | ID: mdl-25803850

ABSTRACT

Glioblastoma (GBM) is the most prevalent adult brain tumor, with virtually no cure, and with a median overall survival of 15 months from diagnosis despite of the treatment. SNARE proteins mediate membrane fusion events in cells and are essential for many cellular processes including exocytosis and neurotransmission, intracellular trafficking and cell migration. Here we show that the blockade of the SNARE protein Syntaxin 1 (Stx1) function impairs GBM cell proliferation. We show that Stx1 loss-of-function in GBM cells, through ShRNA lentiviral transduction, a Stx1 dominant negative and botulinum toxins, dramatically reduces the growth of GBM after grafting U373 cells into the brain of immune compromised mice. Interestingly, Stx1 role on GBM progression may not be restricted just to cell proliferation since the blockade of Stx1 also reduces in vitro GBM cell invasiveness suggesting a role in several processes relevant for tumor progression. Altogether, our findings indicate that the blockade of SNARE proteins may represent a novel therapeutic tool against GBM.


Subject(s)
Botulinum Toxins/pharmacology , Cell Proliferation/drug effects , Glioblastoma/physiopathology , RNA, Small Interfering/pharmacology , Syntaxin 1/antagonists & inhibitors , Animals , Blotting, Western , Bromodeoxyuridine , Cell Line, Tumor , Flow Cytometry , Glioblastoma/drug therapy , Humans , Lentivirus , Mice , Neoplasm Invasiveness/prevention & control , RNA, Small Interfering/genetics , Statistics, Nonparametric , Transduction, Genetic/methods
SELECTION OF CITATIONS
SEARCH DETAIL
...