The structure of the C-terminal domain of the protein kinase AtSOS2 bound to the calcium sensor AtSOS3

Disponible en: http://www.xtal.iqfr.csic.es/publications/molcell2007.pdfThe plant SOS2 family of protein kinases and their interacting activators, the SOS3 family of calcium-binding proteins, function together in decoding calcium signals elicited by different environmental stimuli. SOS2 is activated by Ca-SOS3 and subsequently phosphorylates the ion transporter SOS1 to bring about cellular ion homeostasis under salt stress. In addition to possessing the kinase activity, members of the SOS2 family of protein kinases can bind to protein phosphatase 2Cs. The crystal structure of the binary complex of Ca-SOS3 with the C-terminal regulatory moiety of SOS2 resolves central questions regarding the dual function of SOS2 as a kinase and a phosphatase-binding protein. A comparison with the structure of unbound SOS3 reveals the basis of the molecular function of this family of kinases and their interacting calcium sensors. Furthermore, our study suggests that the structure of the phosphataseinteraction domain of SOS2 defines a scaffold module conserved from yeast to human.Was supported by a Formacion de Personal Investigador studentship from Ministerio de Educación, Cultura y Deporte, and a Postgraduate I3P Fellowship from the Consejo Superior de Investigaciones Cientificas. A.A. thanks the European Synchrotron Radiation Facility (ESRF) for access to the synchrotron radiation source. This work was funded by the BFU2005-06388-C04-02/BMC grant of the Spanish ‘‘Plan Nacional’’ (MEC) and ‘‘Factoría de Cristalización’’ Consolider Ingenio 2010 to A.A. and by U.S. National Institutes of Health grant R01GM59138 to J.-K.Z.Peer reviewe

Recognition and activation of the plant AkT1 potassium channel by the kinase CIPK23

Plant growth largely depends on the maintenance of adequate intracellular levels of potassium (K1). The families of 10 Calcineurin B-Like (CBL) calcium sensors and 26 CBL-Interacting Protein Kinases (CIPKs) of Arabidopsis (Arabidopsis thaliana) decode the calcium signals elicited by environmental inputs to regulate different ion channels and transporters involved in the control of K1 fluxes by phosphorylation-dependent and -independent events. However, the detailed molecular mechanisms governing target specificity require investigation. Here, we show that the physical interaction between CIPK23 and the noncanonical ankyrin domain in the cytosolic side of the inward-rectifier K1 channel AKT1 regulates kinase docking and channel activation. Point mutations on this domain specifically alter binding to CIPK23, enhancing or impairing the ability of CIPK23 to regulate channel activity. Our data demonstrate the relevance of this protein–protein interaction that contributes to the formation of a complex between CIPK23/CBL1 and AKT1 in the membrane for the proper regulation of K1 transport

Chemotherapy or allogeneic transplantation in high-risk Philadelphia chromosome–negative adult lymphoblastic leukemia

The need for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in adults with Philadelphia chromosome–negative (Ph−) acute lymphoblastic leukemia (ALL) with high-risk (HR) features and adequate measurable residual disease (MRD) clearance remains unclear. The aim of the ALL-HR-11 trial was to evaluate the outcomes of HR Ph− adult ALL patients following chemotherapy or allo-HSCT administered based on end-induction and consolidation MRD levels. Patients aged 15 to 60 years with HR-ALL in complete response (CR) and MRD levels (centrally assessed by 8-color flow cytometry) <0.1% after induction and <0.01% after early consolidation were assigned to receive delayed consolidation and maintenance therapy up to 2 years in CR. The remaining patients were allocated to allo-HSCT. CR was attained in 315/348 patients (91%), with MRD <0.1% after induction in 220/289 patients (76%). By intention-to-treat, 218 patients were assigned to chemotherapy and 106 to allo-HSCT. The 5-year (±95% confidence interval) cumulative incidence of relapse (CIR), overall survival (OS), and event-free survival probabilities for the whole series were 43% ± 7%, 49% ± 7%, and 40% ± 6%, respectively, with CIR and OS rates of 45% ± 8% and 59% ± 9% for patients assigned to chemotherapy and of 40% ± 12% and 38% ± 11% for those assigned to allo-HSCT, respectively. Our results show that avoiding allo-HSCT does not hamper the outcomes of HR Ph− adult ALL patients up to 60 years with adequate MRD response after induction and consolidation. Better postremission alternative therapies are especially needed for patients with poor MRD clearance

Estructura y mecanismo de acción del regulador SOS3 respuesta al estrés salino en la ruta SOS

El exceso de sal en los suelos inhibe el crecimiento de las plantas y causa grandes pérdidas en la producción agrícola mundial. La ruta Salt Overly Sensitive (SOS) juega un papel determinante en la tolerancia salina en plantas y el control de las concentraciones de ión sodio (Na+) en el citosol, de ahí que el establecimiento de las bases estructurales de dicho proceso sea de gran importancia para entender la función molecular del sistema y para poder en un futuro darle una aplicación biotecnológica. El sensor de Ca2+ SOS3 es una proteína clave en la ruta SOS, ya que se encarga de iniciar la respuesta para la tolerancia salina. SOS3 es capaz de sentir la señal citosólica del Ca2+ provocada por el estrés salino, para posteriormente activar a la quinasa SOS2. Con el fin de entender cómo SOS3 une el Ca2+ y regula la actividad de SOS2, y comprender en última instancia cómo funciona específicamente mediando la señal proveniente del estrés salino y no de otros tipos de estreses que pueden también provocar cambios en la concentración citosólica de Ca2+, se ha abordado el estudio estructural de esta proteína. Se ha determinado la estructura tridimensional mediante difracción de rayos X de los complejos SOS3 Ca2+ y SOS3 Mn2+ Ca2+, se han realizado experimentos de ultracentrifugación analítica para caracterizar el estado de asociación de la proteína en función de diversos cationes fisiológicamente relevantes, se han realizado experimentos de desnaturalización térmica registrada por dicroísmo circular para caracterizar la unión de dichos metales, se han llevado a cabo experimentos de cromatografía de interacción hidrofóbica para estudiar el carácter hidrofóbico de SOS3 y por último, se ha comparado estructuralmente SOS3 con sus proteínas homólogas para poner de manifiesto los determinantes estructurales asociados a sus propiedades.La integración de todos los resultados han permitido proponer un mecanismo de respuesta al Ca2+ e interacción con SOS2 según el cual la unión del Ca2+ a SOS3 provoca un cambio conformacional que induce la dimerización de la proteína y un aumento del carácter hidrofóbico de la misma. Esto permite la interacción de SOS3 con SOS2 y la activación de la quinasa

Structural Biology of a Major Signaling Network that Regulates Plant Abiotic Stress: The CBL-CIPK Mediated Pathway

The Arabidopsis SOS2 family of twenty-six protein kinases (CIPKs), their interacting activators, the SOS3 family of ten calcium-binding proteins (CBLs) and protein phosphatases type 2C (PP2C), function together in decoding calcium signals elicited by different environmental stimuli. Biochemical data suggest that stable CBL-CIPK or CIPK-PP2C complexes may be regulating the activity of various substrates controlling ion homeostasis. The available structural information provides a general regulatory mechanism in which calcium perception by CBLs and kinase activation is coupled. The structural basis of this molecular mechanism and the specificity of the network is reviewed and discussed in detail

Structural Biology of a Major Signaling Network that Regulates Plant Abiotic Stress: The CBL-CIPK Mediated Pathway

The Arabidopsis SOS2 family of twenty-six protein kinases (CIPKs), their interacting activators, the SOS3 family of ten calcium-binding proteins (CBLs) and protein phosphatases type 2C (PP2C), function together in decoding calcium signals elicited by different environmental stimuli. Biochemical data suggest that stable CBL-CIPK or CIPK-PP2C complexes may be regulating the activity of various substrates controlling ion homeostasis. The available structural information provides a general regulatory mechanism in which calcium perception by CBLs and kinase activation is coupled. The structural basis of this molecular mechanism and the specificity of the network is reviewed and discussed in detail.This work was funded by grants BIO2011-28184-C02-02 to M.J.S.-B. and BFU2011-25384 to A.A. M.J.S.-B. was supported by a Ramón y Cajal contract RYC-2008-03449. Our apologies to those whose work could not be included due to space constraints

Frq2 from Drosophila melanogaster: Cloning, expression, purification, crystallization and preliminary X-ray analysis

Drosophila melanogaster contains two calcium-binding proteins, Frq1 and Frq2, in the nervous system that control the number of synapses and the probability of release. To understand the differential function of the two proteins, whose sequence is only 5% dissimilar, the crystal structures of Frq1 and Frq2 are needed. Here, the cloning, expression, purification, crystallization and preliminary crystallographic analysis of Frq2 are presented. The full-length protein was purified using a two-step chromatographic procedure. Two different diffracting crystal forms were obtained using a progressive streak-seeding method and detergents. © 2014 International Union of Crystallography All rights reserved.Peer Reviewe

Acilhidrazonas para el tratamiento de enfermedades neurológicas

La presente invención se refiere a un grupo de compuestos con un núcleo estructural de acilhidrazona que presentan capacidad moduladora de la interacción entre las proteínas NCS-1 y Ric8a, implicadas en el proceso de regulación del número de sinapsis y la probabilidad de liberación de neurotransmisores.Estos compuestos, por tanto, son útiles para el tratamiento de enfermedades neurológicas en las que está afectado el número de sinapsis, tales como enfermedad de Alzheimer, enfermedad de Huntington o enfermedad de Parkinson. [ES]The invention relates to a group of compounds with a structural nucleus of acylhydrazone, which are capable of modulating the interaction between the proteins NCS-1 and Ric8a involved in the process of regulating the number of synapses and the probability of release of neurotransmitters. These compounds can therefore be used for the treatment of neurological diseases in which the number of synapses is affected, such as Alzheimer's disease, Huntington's disease or Parkinson's disease. [EN]Peer reviewedConsejo Superior de Investigaciones Científicas (España), Fundación para la Investigación Biomédica del Hospital Universitario Ramón y CajalA1 Solicitud de patente con informe sobre el estado de la técnic

Preliminary crystallographic analysis of the ankyrin-repeat domain of Arabidopsis thaliana AKT1: Identification of the domain boundaries for protein crystallization

The Arabidopsis thaliana K+ transporter 1 (AKT1) participates in the maintenance of an adequate cell potassium (K+) concentration. The CBL-interacting protein kinase 23 (CIPK23) activates AKT1 for K+ uptake under low-K+ conditions. This process is mediated by the interaction between the cytosolic ankyrin-repeat (AR) domain of AKT1 and the kinase domain of CIPK23. However, the precise boundaries of the AR domain and the residues responsible for the interaction are still unknown. Here, the optimization procedure to obtain an AR domain construct suitable for crystallization and the preliminary crystallographic analysis of the obtained crystals are reported. The crystals belonged to space group P21212, with unit-cell parameters a = 34.83, b = 65.89, c = 85.44 Å, and diffracted to 1.98 Å resolution. © 2014 International Union of Crystallography All rights reserved.Peer Reviewe