Person: Rodríguez Escudero, María Isabel
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First Name
María Isabel
Last Name
Rodríguez Escudero
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Microbiología y Parasitología
Area
Microbiología
Identifiers
10 results
Search Results
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Item Heterologous mammalian Akt disrupts plasma membrane homeostasis by taking over TORC2 signaling in Saccharomyces cerevisiae(Scientific Reports, 2018) Rodríguez Escudero, María Isabel; Fernández-Acero Bascones, Teresa; Jiménez Cid, Víctor; Molina Martín, MaríaThe Akt protein kinase is the main transducer of phosphatidylinositol-3,4,5-trisphosphate (PtdIns3,4,5P3) signaling in higher eukaryotes, controlling cell growth, motility, proliferation and survival. By co-expression of mammalian class I phosphatidylinositol 3-kinase (PI3K) and Akt in the Saccharomyces cerevisiae heterologous model, we previously described an inhibitory effect on yeast growth that relied on Akt kinase activity. Here we report that PI3K-Akt expression in yeast triggers the formation of large plasma membrane (PM) invaginations that were marked by actin patches, enriched in PtdIns4,5P2 and associated to abnormal intracellular cell wall deposits. These effects of Akt were mimicked by overproduction of the PtdIns4,5P2 effector Slm1, an adaptor of the Ypk1 and Ypk2 kinases in the TORC2 pathway. Although Slm1 was phosphorylated in vivo by Akt, TORC2-dependent Ypk1 activation did not occur. However, PI3K-activated Akt suppressed the lethality derived from inactivation of either TORC2 or Ypk protein kinases. Thus, heterologous co-expression of PI3K and Akt in yeast short-circuits PtdIns4,5P2- and TORC2-signaling at the level of the Slm-Ypk complex, overriding some of its functions. Our results underscore the importance of phosphoinositide-dependent kinases as key actors in the homeostasis and dynamics of the PM.- Project number: 265
Item SWI@UCM 2.0: Consolidación de Small World Initiative: descubrimiento y uso racional de antibióticos mediante aprendizaje-servicio en la Comunidad de Madrid(2018) Jiménez Cid, Víctor; Rodríguez Escudero, María Isabel; Díez Orejas, Rosalía María; Molina Martín, María; Rodríguez Fernández, Carmina; Navarro García, Federico; Arroyo Nombela, Francisco Javier; Román González, Elvira; Martín Brieva, Humberto; Fernández-Acero Bascones, Teresa; Sanz Santamaría, Ana Belén; Díaz Del Toro, Silvia; Calvo De Pablo, Pilar; Patiño Álvarez, Aurora Belén; González Zorn, Bruno; Suárez Rodríguez, Mónica; Goyache Goñi, Joaquín; Escudero García-Calderón, José Antonio; Prieto Prieto, Antonio Daniel; Ugarte Ruiz, María; Gil Serna, JessicaDurante el curso anterior un equipo de la UCM en el marco de un proyecto previo INNOVA-Docencia UCM instauró en España de manera pionera la iniciativa de aprendizaje activo Small World Initiative, de origen norteamericano. Los objetivos de esta iniciativa son (1) Crear cultura científica y acercar la investigación biomédica a niveles educativos en los que los estudiantes tienen aún capacidad de decisión sobre su futura orientación formativa con el fin de fomentar la vocación en I+D; y (2) Promover la concienciación social sobre el uso racional de los antibióticos y la amenaza de la resistencia bacteriana a estos fármacos. En el entorno español se propuso implementar esta estrategia mediante Aprendizaje-Servicio. En esta segunda edición (SWI@UCM 2.0) se ha trabajado en la consolidación, expansión y mejora del proyecto, con énfasis en la integración de los diversos niveles educativos que integran el proyecto (universitario y preuniversitario) y la divulgación científica. Item Studying Coxiella burnetii Type IV Substrates in the Yeast Saccharomyces cerevisiae: Focus on Subcellular Localization and Protein Aggregation.(PloS one, 2016) Cid, Víctor J.; Molina, María; Schulze Luehrmann, Jan; Lührmann, Anja; Rodríguez Escudero, María IsabelCoxiella burnetii is a Gram-negative obligate parasitic bacterium that causes the disease Q-fever in humans. To establish its intracellular niche, it utilizes the Icm/Dot type IVB secretion system (T4BSS) to inject protein effectors into the host cell cytoplasm. The host targets of most cognate and candidate T4BSS-translocated effectors remain obscure. We used the yeast Saccharomyces cerevisiae as a model to express and study six C. burnetii effectors, namely AnkA, AnkB, AnkF, CBU0077, CaeA and CaeB, in search for clues about their role in C. burnetii virulence. When ectopically expressed in HeLa cells, these effectors displayed distinct subcellular localizations. Accordingly, GFP fusions of these proteins produced in yeast also decorated distinct compartments, and most of them altered cell growth. CaeA was ubiquitinated both in yeast and mammalian cells and, in S. cerevisiae, accumulated at juxtanuclear quality-control compartments (JUNQs) and insoluble protein deposits (IPODs), characteristic of aggregative or misfolded proteins. AnkA, which was not ubiquitinated, accumulated exclusively at the IPOD. CaeA, but not AnkA or the other effectors, caused oxidative damage in yeast. We discuss that CaeA and AnkA behavior in yeast may rather reflect misfolding than recognition of conserved targets in the heterologous system. In contrast, CBU0077 accumulated at vacuolar membranes and abnormal ER extensions, suggesting that it interferes with vesicular traffic, whereas AnkB associated with the yeast nucleolus. Both effectors shared common localization features in HeLa and yeast cells. Our results support the idea that C. burnetii T4BSS effectors manipulate multiple host cell targets, which can be conserved in higher and lower eukaryotic cells. However, the behavior of CaeA and AnkA prompt us to conclude that heterologous protein aggregation and proteostatic stress can be a limitation to be considered when using the yeast model to assess the function of bacterial effectors.Item Heterologous mammalian Akt disrupts plasma membrane homeostasis by taking over TORC2 signaling in Saccharomyces cerevisiae.(Scientific Reports, 2018) Rodríguez Escudero, María Isabel; Fernández-Acero Bascones, Teresa; Jiménez Cid, Víctor; Molina, MaríaThe Akt protein kinase is the main transducer of phosphatidylinositol-3,4,5-trisphosphate (PtdIns3,4,5P) signaling in higher eukaryotes, controlling cell growth, motility, proliferation and survival. By co-expression of mammalian class I phosphatidylinositol 3-kinase (PI3K) and Akt in the Saccharomyces cerevisiae heterologous model, we previously described an inhibitory effect on yeast growth that relied on Akt kinase activity. Here we report that PI3K-Akt expression in yeast triggers the formation of large plasma membrane (PM) invaginations that were marked by actin patches, enriched in PtdIns4,5P and associated to abnormal intracellular cell wall deposits. These effects of Akt were mimicked by overproduction of the PtdIns4,5P effector Slm1, an adaptor of the Ypk1 and Ypk2 kinases in the TORC2 pathway. Although Slm1 was phosphorylated in vivo by Akt, TORC2-dependent Ypk1 activation did not occur. However, PI3K-activated Akt suppressed the lethality derived from inactivation of either TORC2 or Ypk protein kinases. Thus, heterologous co-expression of PI3K and Akt in yeast short-circuits PtdIns4,5P- and TORC2-signaling at the level of the Slm-Ypk complex, overriding some of its functions. Our results underscore the importance of phosphoinositide-dependent kinases as key actors in the homeostasis and dynamics of the PM.Item A yeast-based in vivo bioassay to screen for class I phosphatidylinositol 3-kinase specific inhibitors.(Journal of biomolecular screening, 2012) Fernández-Acero Bascones, Teresa; Rodríguez Escudero, María Isabel; Vicente, Francisca; Monteiro, Maria Cândida; Tormo, José R.; Cantizani, Juan; Molina, María; Cid, Víctor J.The phosphatidylinositol 3-kinase (PI3K) pathway couples receptor-mediated signaling to essential cellular functions by generating the lipid second messenger phosphatidylinositol-3,4,5-trisphosphate. This pathway is implicated in multiple aspects of oncogenesis. A low-cost bioassay that readily measures PI3K inhibition in vivo would serve as a valuable tool for research in this field. Using heterologous expression, we have previously reconstituted the PI3K pathway in the model organism Saccharomyces cerevisiae. On the basis of the fact that the overproduction of PI3K is toxic in yeast, we tested the ability of commercial PI3K inhibitors to rescue cell growth. All compounds tested counteracted the PI3K-induced toxicity. Among them, 15e and PI-103 were the most active. Strategies to raise the intracellular drug concentration, specifically the use of 0.003% sodium dodecyl sulfate and the elimination of the Snq2 detoxification pump, optimized the bioassay by enhancing its sensitivity. The humanized yeast-based assay was then tested on a pilot scale for high-throughput screening (HTS) purposes using a collection of natural products of microbial origin. From 9600 extracts tested, 0.6% led to a recovery of yeast growth reproducibly, selectively, and in a dose-dependent manner. Cumulatively, we show that the developed PI3K inhibition bioassay is robust and applicable to large-scale HTS.Item A pathogenic role for germline PTEN variants which accumulate into the nucleus.(European journal of human genetics, 2018) Mingo, Janire; Rodríguez Escudero, María Isabel; Luna, Sandra; Fernández Acero, Teresa; Amo, Laura; Jonasson, Amy R; Zori, Roberto T; López, José I; Molina, María; Cid, Víctor J.; Pulido, RafaelThe PTEN gene encodes a master regulator protein that exerts essential functions both in the cytoplasm and in the nucleus. PTEN is mutated in the germline of both patients with heterogeneous tumor syndromic diseases, categorized as PTEN hamartoma tumor syndrome (PHTS), and a group affected with autism spectrum disorders (ASD). Previous studies have unveiled the functional heterogeneity of PTEN variants found in both patient cohorts, making functional studies necessary to provide mechanistic insights related to their pathogenicity. Here, we have functionally characterized a PTEN missense variant [c.49C>G; p.(Gln17Glu); Q17E] associated to both PHTS and ASD patients. The PTEN Q17E variant displayed partially reduced PIP3-catalytic activity and normal stability in cells, as shown using S. cerevisiae and mammalian cell experimental models. Remarkably, PTEN Q17E accumulated in the nucleus, in a process involving the PTEN N-terminal nuclear localization sequence. The analysis of additional germline-associated PTEN N-terminal variants illustrated the existence of a PTEN N-terminal region whose targeting in disease causes PTEN nuclear accumulation, in parallel with defects in PIP3-catalytic activity in cells. Our findings highlight the frequent occurrence of PTEN gene mutations targeting PTEN N-terminus whose pathogenicity may be related, at least in part, with the retention of PTEN in the nucleus. This could be important for the implementation of precision therapies for patients with alterations in the PTEN pathway.Item Expression of Human PTEN-L in a Yeast Heterologous Model Unveils Specific N-Terminal Motifs Controlling PTEN-L Subcellular Localization and Function(Cells, 2019) Fernández-Acero Bascones, Teresa; Bertalmio, Eleonora; Luna, Sandra; Mingo, Janire; Bravo Plaza, Ignacio; Rodríguez Escudero, María Isabel; Molina Martín, María; Pulido, Rafael; Jiménez Cid, VíctorThe tumour suppressor PTEN is frequently downregulated, mutated or lost in several types of tumours and congenital disorders including PHTS (PTEN Hamartoma Tumour Syndrome) and ASD (Autism Spectrum Disorder). PTEN is a lipid phosphatase whose activity over the lipid messenger PIP3 counteracts the stimulation of the oncogenic phosphatidylinositol 3-kinase (PI3K) pathway. Recently, several extended versions of PTEN produced in the cell by alternative translation initiation have been described, among which, PTEN-L and PTEN-M represent the longest isoforms. We previously developed a humanized yeast model in which the expression of PI3K in Saccharomyces cerevisiae led to growth inhibition that could be suppressed by co-expression of PTEN. Here, we show that the expression of PTEN-L and PTEN-M in yeast results in robust counteracting of PI3K-dependent growth inhibition. N-terminally tagged GFP-PTEN-L was sharply localized at the yeast plasma membrane. Point mutations of a putative membrane-binding helix located at the PTEN-L extension or its deletion shifted localization to nuclear. Also, a shift from plasma membrane to nucleus was observed in mutants at basic amino acid clusters at the PIP2-binding motif, and at the Cα2 and CBR3 loops at the C2 domain. In contrast, C-terminally tagged PTEN-L-GFP displayed mitochondrial localization in yeast, which was shifted to plasma membrane by removing the first 22 PTEN-L residues. Our results suggest an important role of the N-terminal extension of alternative PTEN isoforms on their spatial and functional regulation.Item A functional dissection of PTEN N-terminus: implications in PTEN subcellular targeting and tumor suppressor activity.(PloS one, 2015) Gil, Anabel; Rodríguez Escudero, María Isabel; Stumpf, Miriam; Molina Martín, María; Jiménez Cid, Víctor; Pulido, RafaelSpatial regulation of the tumor suppressor PTEN is exerted through alternative plasma membrane, cytoplasmic, and nuclear subcellular locations. The N-terminal region of PTEN is important for the control of PTEN subcellular localization and function. It contains both an active nuclear localization signal (NLS) and an overlapping PIP2-binding motif (PBM) involved in plasma membrane targeting. We report a comprehensive mutational and functional analysis of the PTEN N-terminus, including a panel of tumor-related mutations at this region. Nuclear/cytoplasmic partitioning in mammalian cells and PIP3 phosphatase assays in reconstituted S. cerevisiae defined categories of PTEN N-terminal mutations with distinct PIP3 phosphatase and nuclear accumulation properties. Noticeably, most tumor-related mutations that lost PIP3 phosphatase activity also displayed impaired nuclear localization. Cell proliferation and soft-agar colony formation analysis in mammalian cells of mutations with distinctive nuclear accumulation and catalytic activity patterns suggested a contribution of both properties to PTEN tumor suppressor activity. Our functional dissection of the PTEN N-terminus provides the basis for a systematic analysis of tumor-related and experimentally engineered PTEN mutations.Item Yeast-based methods to assess PTEN phosphoinositide phosphatase activity in vivo(Methods, 2015) Rodríguez Escudero, María Isabel; Fernández-Acero Bascones, Teresa; Bravo, Ignacio; Leslie, Nicholas R.; Pulido, Rafael; Molina, María; Jiménez Cid, VíctorThe PTEN phosphoinositide 3-phosphatase is a tumor suppressor commonly targeted by pathologic missense mutations. Subject to multiple complex layers of regulation, its capital role in cancer relies on its counteracting function of class I phosphoinositide 3-kinase (PI3K), a key feature in oncogenic signaling pathways. Precise assessment of the involvement of PTEN mutations described in the clinics in loss of catalytic activity requires either tedious in vitro phosphatase assays or in vivo experiments involving transfection into mammalian cell lines. Taking advantage of the versatility of the model organism Saccharomyces cerevisiae, we have developed different functional assays by reconstitution of the mammalian PI3K-PTEN switch in this lower eukaryote. This methodology is based on the fact that regulated PI3K expression in yeast cells causes conversion of PtdIns(4,5)P2 in PtdIns(3,4,5)P3 and co-expression of PTEN counteracts this effect. This can be traced by monitoring growth, given that PtdIns(4,5)P2 pools are essential for the yeast cell, or by using fluorescent reporters amenable for microscopy or flow cytometry. Here we describe the methodology and review its application to evaluate the functionality of PTEN mutations. We show that the technique is amenable to both directed and systematic structure-function relationship studies, and present an example of its use for the study of the recently discovered PTEN-L variantItem The yeast cell wall integrity pathway signals from recycling endosomes upon elimination of phosphatidylinositol (4,5)-bisphosphate by mammalian phosphatidylinositol 3-kinase.(Cellular signalling, 2015) Fernández-Acero Bascones, Teresa; Rodríguez Escudero, María Isabel; Molina, María; Jiménez Cid, VíctorPhosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] is essential for recognition of the plasma membrane inner leaf by protein complexes. We expressed mammalian class I phosphoinositide 3-kinase (PI3K) in Saccharomyces cerevisiae to eliminate PtdIns(4,5)P2 by its conversion into PtdIns(3,4,5)P3, a lipid naturally missing in this yeast. This led to loss of actin function and endocytosis defects, causing a blockage in polarized secretion. Also, the cell wall integrity (CWI) mitogen-activated protein kinase (MAPK) pathway was activated, triggering a typical transcriptional response. In the absence of PtdIns(4,5)P2 at the plasma membrane, the Pkc1 protein kinase upstream the CWI MAPK module localized to post-Golgi endosomes marked by SNARE Snc1 and Rab GTPases Ypt31 and Ypt32. Other components at the head of the pathway, like the mechanosensor Wsc1, the GTPase Rho1 and its activator the GDP/GTP exchange factor Rom2, co-localized with Pkc1 in these compartments. Chemical inhibition of PI3K proved that both CWI activation and Pkc1 relocation to endosomes are reversible. These results suggest that the CWI pathway is able to respond to loss of plasma membrane identity from recycling endosomes.