Dinámica de septinas y regulación de la separación celular durante el crecimiento hifal de Candida albicans ¿una diana de antifúngicos?

Resumen del trabajo presentado al "IV Congreso GEBMP: Simposio Hongos Patógenos" celebrado en Badajoz el 6 de julio del 2012.Peer Reviewe

A membrane-associated form of the transcription factor Ace2 controls septin ring dynamics during Candida albicans hyphal growth

Resumen del trabajo presentado a la Vth International Conference on Molecular Mechanisms of Fungal Cell Wall Biogenesis celebrada en Primosten (Croacia) del 6 al 9 de Junio de 2012.Peer Reviewe

A formin-nucleated actin aster concentrates cell wall hydrolases for cell fusion in fission yeast.

Cell-cell fusion is essential for fertilization. For fusion of walled cells, the cell wall must be degraded at a precise location but maintained in surrounding regions to protect against lysis. In fission yeast cells, the formin Fus1, which nucleates linear actin filaments, is essential for this process. In this paper, we show that this formin organizes a specific actin structure-the actin fusion focus. Structured illumination microscopy and live-cell imaging of Fus1, actin, and type V myosins revealed an aster of actin filaments whose barbed ends are focalized near the plasma membrane. Focalization requires Fus1 and type V myosins and happens asynchronously always in the M cell first. Type V myosins are essential for fusion and concentrate cell wall hydrolases, but not cell wall synthases, at the fusion focus. Thus, the fusion focus focalizes cell wall dissolution within a broader cell wall synthesis zone to shift from cell growth to cell fusion

International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved

Cdc14 is released from the nucleolus under DNA damage and is required for DNA repair by homologous recombination

Resumen del póster presentado al XXXIX Congreso de la Sociedad Española de Bioquímica y Biología Molecular, celebrado en Salamanca del 5 al 8 de septiembre de 2016.Endogenous metabolic products, such as reactive oxygen species, and exogenous genotoxic stress, constantly assault the genetic material in the cell. In response to these sources of DNA damage, cells have developed a coordinated signalling network known as the DDR (DNA damage response), which coordinates cell cycle progression with DNA repair. Recently, multiple lines of evidences have suggested a complex role for several kinases in the regulation of the DDR (including the CDK), but little is known about the phosphatases that revert the effects of these kinases. The serine/threonine phosphatase Cdc14 was firstly identify in S. cerevisiae as an essential cell cycle phosphatase required for Cdk inactivation. This phosphatase is sequestered into the nucleolus during interphase due to its interaction with Net1. During anaphase, Net1 is phosphorylated and Cdc14 is released from the nucleolus to allow cells exit from mitosis. Cdc14 has predisposition to dephosphorylate Cdk targets, therefore is reasonable to think that could be a key candidate to counterbalance the effect imposed by the Cdk in the DDR. In favour of this hypothesis, Cdc14 is required for cell viability under different DNA damage conditions. To determine the role of the phosphatase in the DDR, we used two different recombinational repair pathways: SDSA (Synthensis dependent strand annealing) and dHJ (double Holliday junction repair). We observed that cells lacking Cdc14 activity presented defects in DNA repair in both SDSA and dHJ. Supporting the role of the phosphatase in DNA repair, we observed that Cdc14 was released from the nucleolus after induction of a single DSB or treatment with phleomycin. Accordingly, Net1 was phosphorylated during the execution of the DDR. Finally, by using mass spectrometry in a screen to identify targets of the phosphatase exclusively in DNA damage, we have detected several targets directly implicated in DNA damage repair. Altogether, we have placed Cdc14 at the DNA damage response context by collaborating in the repair throughout the modulation of the homologous recombination repair pathway, and providing new evidences about the role of this phosphatase in the repair of a DNA lesion.Peer Reviewe

Cdc14 is required for DNA repair by homologous recombination

Resumen del póster presentado al XL Congreso de la Sociedad Española de Genética, celebrado en Córdoba del 16 al 18 de septiembre de 2015.Endogenous metabolic products, such as reactive oxygen species, and exogenous physical and chemical genotoxic stress, constantly assault the genetic material in the cell. It has been estimated that there are about 105 lesions per cell per day in humans. In response to such a high levels of DNA damage, cells have developed a coordinated signalling network known as the DDR (DNA damage response), which coordinate cell cycle progression with DNA repair. When this system fail or the rate of DNA damage exceeds the capacity of the pathway to repair them, the accumulation of errors can overwhelm the cell and result in early senescence, apoptosis, or cancer. Recently, multiple lines of evidences have suggested a complex role for several kinases in the regulation of the DDR (including the CDK), but little is known about the phosphatases that revert the effects of these kinases. The serine/threonine phosphatase Cdc14 was firstly identify in S. cerevisiae as an essential cell cycle phosphatase required for Cdk inactivation. One special feature of this phosphatase is its predisposition to dephosphorylate targets of the Cdk, therefore is reasonable to think that Cdc14 could be a key candidate to counterbalance the effect imposed by the Cdk in the DDR. In favour of this hypothesis, Cdc14 is required for cell viability under different DNA damage conditions. Cells lacking Cdc14 activity present a slow kinetic of DNA repair in two different recombinatorial repair pathways: SDSA (Synthensis dependent strand annealing) and dHR (double Holliday junction repair). These defects are not associated with a slow resection at the break, indicating a later role of the phosphatase in the repair process. Additionally, Cdc14 is not required for determine the choice repair between NHEJ (Non-homologous end joining) and HR (Homologous recombination). Supporting a function of the phosphatase in DNA repair, Cdc14 is release from the nucleolus after induction of a single DSB, colocalizing at the cut site by microscopy and chromatin immunoprecipitation assays. Finally, by using mass spectrometry in a screen to identify targets of Cdc14 exclusively in DNA damage, we have detected several targets directly implicated in DNA damage repair. Altogether, we have placed Cdc14 at the DNA damage response context by collaborating in the repair throughout the modulation of the HR repair pathway, and providing new evidences about the role of this phosphatase in the repair of a DNA lesion.Peer Reviewe

The spindle-stabilization function of Cdc14 is required to promote recombinational DNA repair

Póster presentado al XXXIX Congreso de la Sociedad Española de Bioquímica y Biología Molecular, celebrado en Salamanca del 5 al 8 de septiembre de 2016.Eukaryotic cells are constantly threatened by innumerable sources of genotoxic stresses that cause DNA damage. In order to maintain genome integrity, cells have developed a coordinated signaling network known as the DNA Damage Response (DDR). While numerous kinases have been thoroughly studied during the activation of the DDR, the role of protein phosphatases remains elusive. Previous data coming from our group have revealed the importance of the phosphatase Cdc14 in promoting recombinational DNA repair. However, how this phosphatase exerts its molecular function in the DDR is still unknown. Here we show that a DSB (double strand break) induced by the expression of the HO endonuclease is actively recruited to one of the SPBs (Spindle Pole Bodies). DSB-SPB interaction requires the N-terminus domain of the SPB protein Mps3 and a competent DNA damage checkpoint activation. Curiously, microtubules destabilization by nocodazole treatment during the induction of the DNA break disrupts SPB-DSB interaction and impairs HR (homologous recombination), indicating that SPB integrity and SPB-DSB binding are essential features of the DNA repair process. Surprisingly, inactivation of Cdc14 during the induction of the DNA lesion causes continuous misalignment of the metaphase spindle, increases oscillatory SPBs movements, and impairs DSB-SPB tethering, suggesting a role of the phosphatase in DNA repair by promoting spindle stability. In a screen looking for Cdc14 substrates at the SPBs after the induction of a DNA break, we identified Spc110, the intranuclear receptor for the γ-tubulin complex. Loss of Cdk-dependent Spc110 phosphorylation during DSB induction causes the same phenotypes as cdc14-1 mutants. Together, our results point to the function of Cdc14 in DNA repair by promoting SPB stabilization and SPB-DSB interaction, and suggest that the relocation of damage sites to the SPBs plays an important role in a naturally occurring repair process that minimizes genome instability.Peer Reviewe

The spindle-stabilizing function of Cdc14 is required to promote recombinatorial DNA repair

Póster presentado al XL Congreso de la Sociedad Española de Genética, celebrado en Córdoba del 16 al 18 de septiembre de 2015.Endogenous or exogenous agents that cause genotoxic stress are constantly threatening the genomes of all organisms. In response to a DNA lesion, different processes (collectively known as DDR) are triggered in order to coordinate the repair of the damage with cell cycle progression. While phosphorylation events after DNA damage have been thoroughly studied in the DDR, little is known about the role of dephosphorylation during the response. Previous data coming from our group have revealed the importance of the phosphatase Cdc14 in promoting recombinational DNA repair. Here we show that in response to a DSB (double strand break) induced by the expression of the HO endonuclease, cells block in G2/M with a metaphase spindle aligned along the bud axis. Under this arrest, the DNA break is actively recruited to one of the SPBs (Spindle Pole Bodies). Inactivation of the phosphatase activity causes continuous misalignment of the metaphase spindle, increases oscillatory SPBs movements and impairs DSB-SPB tethering. All these phenotypes can be mimicked in a wild-type strain just by adding the microtubule depolymerizing drug nocodazole or by inactivating Spc110, a component of the SPB and a Cdc14 target during the DDR. Surprisingly, these phenotypes are directly linked to DNA repair, since both nocodazole treatment and lack of Spc110 activity impair DSB repair by HR to the same extent as cdc14-1 mutants. Together, our results point to the function of Cdc14 in DNA repair by promoting SPB stabilization and SPB-DSB interaction, and suggest that the relocation of damage sites to the SPBs plays an important role in a naturally occurring repair process that minimizes genome instability.Peer Reviewe

The importance of the mitotic spindle integrity in DNA repair

Resumen del trabajo presentado al XXXIX Congreso de la Sociedad Española de Bioquímica y Biología Molecular, celebrado en Salamanca del 5 al 8 de septiembre de 2016.Maintenance of genome integrity is a vital aspect of our cellular physiology. Our hereditary information encoded in the DNA is constantly threatened by both endogenous and environmental genotoxic stresses that could alter our genomic material. To combat this threat, eukaryotic cells have evolved a series of mechanisms, collectively known as DDR, to survey several features of the cellular response, including the detection of the lesion, a transient cell cycle arrest and the repair of the broken DNA. During the last years it has becoming clearer the biochemical mechanisms operating at each stage of the DDR. However, little is known about the spatial regulation of their components during the DNA damage response and how the relocation of the DNA lesion itself can influence in the repair process. Interestingly, previous studies have indicated that DNA breaks are re-localized from the nucleoplasm to the nuclear periphery, suggesting that nuclear compartmentalization of DNA lesions could comprise another layer in the regulation of the DNA repair pathway. Nevertheless, whether the nuclear periphery harbours an environment that is permissive for DNA repair and its implications in maintaining genome integrity is a subject that still under debate. Remarkably, new data coming from our group indicate that the cell cycle phosphatase Cdc14 is involved in DNA repair by controlling the tethering of a DNA lesion into the spindle pole body (SPB) region of the nuclear envelope. This function is attained by preserving the integrity of the metaphase spindle, a vital requirement to stimulate DSB-SPB interaction and thus DNA repair. Accordingly, disruption of spindle stability impairs both DSB-SPB interaction and DNA repair by homologous recombination. These observations directly connect spindle integrity with DNA repair and reveal that DSBs are preferentially tethered to the SPBs to be restored. Importantly, this new function of Cdc14 could provide a physiological mechanism that spatially regulates the DNA damage response and therefore the fate of the repair process.Peer Reviewe

Regulation of cell separation during Candida hyphal growth by the Ace2 transcription factor and septins

Resumen del trabajo presentado a la Vth International Conference on Molecular Mechanisms of Fungal Cell Wall Biogenesis celebrada en Primosten (Croacia) del 6 al 9 de Junio de 2012.-- Tambien presentado por Carlos R. Vázquez de Aldana al "International Symposium: Biology and Communications" celebrado en Madrid del 26 al 27 de marzo de 2012.Peer Reviewe