Lamin-like analogues in plants: the characterization of AcNMCP1

24 p.-6 fig.Este artículo pertenece a la Tesis presentada por Malgorzata Ciska con título: "Caracterización de AcNMCP1 una proteína implicada en organización nuclear de plantas."(https://digital.csic.es/handle/10261/98559)The nucleoskeleton of plants contains a peripheral lamina also called plamina, and even though lamins are absent in plants, their roles are still fulfilled in plant nuclei. One of the most intriguing topics in plant biology concerns the identity of lamin protein analogues in plants. Good candidates to play lamin functions in plants are the members of the NMCP (nuclear matrix constituent protein) family, which exhibit the typical tripartite structure of lamins. Here, we describe a bioinformatics analysis and the classification of the NMCP family based on phylogenetic relationships, sequence similarity and the distribution of conserved regions in 76 homologues. In addition, we characterized NMCP1 in the monocot Allium cepa, determining its sequence and structure, biochemical properties and sub-nuclear distribution, and identifying alterations in its expression throughout the root. Our results demonstrate that these proteins exhibit many similarities to lamins (structural organization, conserved regions, subnuclear distribution and solubility) and that they may fulfil the functions of lamins in plants. These findings significantly advance our understanding of the structural proteins of the plant lamina and nucleoskeleton, and they provide a basis for further investigation of the protein networks forming these structures.This work was supported by the Spanish Ministry of Science and Innovation [BFU2010-15900] and CSIC [PIE 201020E019]. Malgorzata Ciska was supported by a Junta de Ampliacion de Estudios grant (JAE): JAEPre_08_00012/JAEPre027.Peer reviewe

RepA-WH1 prionoid: Clues from bacteria on factors governing phase transitions in amyloidogenesis

10 p.-1 fig.In bacterial plasmids, Rep proteins initiate DNA replication by undergoing a structural transformation coupled to dimer dissociation. Amyloidogenesis of the ‘winged-helix’ N-terminal domain of RepA (WH1) is triggered in vitro upon binding to plasmid-specific DNA sequences, and occurs at the bacterial nucleoid in vivo. Amyloid fibers are made of distorted RepA-WH1 monomers that assemble as single or double intertwined tubular protofilaments. RepA-WH1 causes in E. coli an amyloid proteinopathy, which is transmissible from mother to daughter cells, but not infectious, and enables conformational imprinting in vitro and in vivo; i.e. RepA-WH1 is a ‘prionoid’. Microfluidics allow the assessment of the intracellular dynamics of RepA-WH1: bacterial lineages maintain two types (strains-like) of RepA-WH1 amyloids, either multiple compact cytotoxic particles or a single aggregate with the appearance of a fluidized hydrogel that it is mildly detrimental to growth. The Hsp70 chaperone DnaK governs the phase transition between both types of RepA-WH1 aggregates in vivo, thus modulating the vertical propagation of the prionoid. Engineering chimeras between the Sup35p/[PSI*] prion and RepA-WH1 generates [REP-PSI*], a synthetic prion exhibiting strong and weak phenotypic variants in yeast. These recent findings on a synthetic, self-contained bacterial prionoid illuminate central issues of protein amyloidogenesis.Research on RepA-WH1 amyloids at CIBCSIC is currently financed by Spanish MINECO grants BIO2012-30852 and CSD2009-00088.Peer reviewe

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

NMCP/LINC proteins: Putative lamin analogs in plants?

34 p.-2 fig.-2 tab. Este artículo pertenece a la Tesis presentada por Malgorzata Ciska con título: "Caracterización de AcNMCP1 una proteína implicada en organización nuclear de plantas."(https://digital.csic.es/handle/10261/98559)Lamins are the main components of the metazoan lamina, and while the organization of the nuclear lamina of metazoans and plants is similar, there are apparently no genes encoding lamins or most lamin-binding proteins in plants. Thus, the plant lamina is not lamin-based and the proteins that form this structure are still to be characterized. Members of the plant NMCP/LINC/CRWN protein family share the typical tripartite structure of lamins, although the 2 exhibit no sequence similarity. However, given the many similarities between NMCP/LINC/CRWN proteins and lamins (structural organization, position of conserved regions, sub-nuclear distribution, solubility, and pattern of expression), these proteins are good candidates to carry out the functions of lamins in plants. Moreover, functional analysis of NMCP/LINC mutants has revealed their involvement in maintaining nuclear size and shape, another activity fulfilled by lamins. This review summarizes the current understanding of NMCP/LINC proteins and discusses future studies that will be required to demonstrate definitively that these proteins are plant analogs of lamins. © 2013 Landes Bioscience.We acknowledge support from the Spanish Ministry of Science and Innovation [BFU2010–15900] and the CSIC [PIE 201020E019]. Ciska M was supported by a grant from the Junta de Ampliación de Estudios (JAEPre_08_00012/JAEPre027) and by PIE 201020E019.Peer reviewe

The intriguing plant nuclear lamina

13 p.-4 fig.-1 tab.The nuclear lamina is a complex protein mesh attached to the inner nuclear membrane(INM),which is also associated with nuclear pore complexes.It provides mechanical support to the nucleus and nuclear envelope,and as well as facilitating the connection of the nucleoskeleton to the cytoskeleton,it is also involved in chromatin organization,gene regulation,and signaling.In metazoans,the nuclear lamina consists of a polymeric layer of lamins and other interacting proteins responsible for its association with the INM and chromatin.In plants,field emission scanning electron microscopy of nuclei,and thin section transmission electron microscopy of isolated nucleoskeletons,reveals the lamina to have a similar structure to that of metazoans.Moreover,although plants lack lamin genes and the genes encoding most lamin-binding proteins,the main functions of the lamina are fulfilled in plants.Hence,it would appear that the plant lamina is not based on lamins and that other proteins substitute for lamins in plant cells.The nuclear matrix constituent proteins are the best characterized structural proteins in the plant lamina.Although these proteins do not display strong sequence similarity to lamins,their predicted secondary structure and sub-nuclear distribution,as well as their influence on nuclear size and shape,and on heterochromatin organization,suggest they could be functional lamin analogs.In this review we shall summarize what is currently known about the organization and composition of the plant nuclear lamina and its interacting complexes,and we will discuss the activity of this structure in the plant cell and its nucleus.We acknowledge the support from the Spanish Ministry of Science and Innovation[BFU2010-15900]and the CSIC[PIE 201020E019].Malgorzata Ciska was supported by a grant from the Junta de Ampliación de Estudios (JAEPre_08_00012/JAEPre027) and by PIE201020E019.Peer reviewe

Demostración mediante técnicas de spreading de la existencia de un esqueleto proteínico en el nucleolo implicado en el procesamiento de los precursores ribosómicos

Trabajo presentado en las XV Jornadas Luso-Españolas de Genética, celebradas en Lisboa (Portugal) el 15 de septiembre de 1979

Caracterización de la matriz esquelética del nucleolo mediante técnicas de spreading

Trabajo presentado en la IX Reunión Bienal de la Sociedad Española de Microscopía Electrónica, celebrada en Las Palmas de Gran Canaria (España) en octubre de 1980

Investigaciones sobre los componentes ribonucleoproteicos de la matriz intranuclear de plantas superiores

Trabajo presentado en la XIV Reunión Bienal de la SEME, celebrado en Ávila (España) del 29 al 31 de octubre de 1986

Organización y composición de los filamentos del nucleoesqueleto en plantas

Trabajo presentado en el VII Congreso de la SEBC, celebrado en España el 15 de diciembre de 1997