The Relationship between AGAMOUS and Cytokinin Signaling in the Establishment of Carpeloid Features.

Gynoecium development is dependent on gene regulation and hormonal pathway interactions. The phytohormones auxin and cytokinin are involved in many developmental programs, where cytokinin is normally important for cell division and meristem activity, while auxin induces cell differentiation and organ initiation in the shoot. The MADS-box transcription factor AGAMOUS (AG) is important for the development of the reproductive structures of the flower. Here, we focus on the relationship between AG and cytokinin in Arabidopsis thaliana, and use the weak ag-12 and the strong ag-1 allele. We found that cytokinin induces carpeloid features in an AG-dependent manner and the expression of the transcription factors CRC, SHP2, and SPT that are involved in carpel development. AG is important for gynoecium development, and contributes to regulating, or else directly regulates CRC, SHP2, and SPT. All four genes respond to either reduced or induced cytokinin signaling and have the potential to be regulated by cytokinin via the type-B ARR proteins. We generated a model of a gene regulatory network, where cytokinin signaling is mainly upstream and in parallel with AG activity.

A procedure combining molecular docking and semiempirical method PM7 for identification of selective Shp2 inhibitors.

Shp2 and Shp1 make up a small family of protein tyrosine phosphatases. Finding selective inhibitors for Shp2 is useful because although its inhibition is advantageous for the treatment of some types of cancer, inhibition of Shp1 may have the opposite effect, since it acts as a suppressor of tumors. We combined molecular docking and semiempirical molecular orbital-based calculations to produce data that were effective for the identification of selective inhibitors for Shp2. After definition of the interaction modes of the inhibitors with Shp2 and Shp1 by molecular docking, the resulting interaction enthalpy values were calculated following refinement of the enzyme/inhibitor complexes' geometries with the PM7 semiempirical molecular orbital method. Despite the complexity of the thermodynamics involved in the enzyme/inhibitor interaction, the selectivity for Shp2 of a series of 76 inhibitors, divided in two groups, could be effectively correlated with the difference in their interaction enthalpy values with both enzymes. For the first group, composed by 52 Shp2-selective indoline inhibitors for which only Shp2 inhibition activity data are available, we demonstrated that the interaction enthalpy can be used as a criterion for identification of selective Shp2 inhibitors, as it is significantly more favorable for Shp2 than Shp1 at a 99% confidence level. For the second group, composed by 24 oxindole derivatives with available Shp2 and Shp1 inhibition activity data, a satisfactory correlation (R = 0.70) could be obtained between the selectivity, based on the IC50 data, and the relative percentage difference of the calculated interaction enthalpies with the two enzymes.

Role of Protein Phosphorylation and Tyrosine Phosphatases in the Adrenal Regulation of Steroid Synthesis and Mitochondrial Function.

In adrenocortical cells, adrenocorticotropin (ACTH) promotes the activation of several protein kinases. The action of these kinases is linked to steroid production, mainly through steroidogenic acute regulatory protein (StAR), whose expression and activity are dependent on protein phosphorylation events at genomic and non-genomic levels. Hormone-dependent mitochondrial dynamics and cell proliferation are functions also associated with protein kinases. On the other hand, protein tyrosine dephosphorylation is an additional component of the ACTH signaling pathway, which involves the "classical" protein tyrosine phosphatases (PTPs), such as Src homology domain (SH) 2-containing PTP (SHP2c), and members of the MAP kinase phosphatase (MKP) family, such as MKP-1. PTPs are rapidly activated by posttranslational mechanisms and participate in hormone-stimulated steroid production. In this process, the SHP2 tyrosine phosphatase plays a crucial role in a mechanism that includes an acyl-CoA synthetase-4 (Acsl4), arachidonic acid (AA) release and StAR induction. In contrast, MKPs in steroidogenic cells have a role in the turn-off of the hormonal signal in ERK-dependent processes such as steroid synthesis and, perhaps, cell proliferation. This review analyzes the participation of these tyrosine phosphates in the ACTH signaling pathway and the action of kinases and phosphatases in the regulation of mitochondrial dynamics and steroid production. In addition, the participation of kinases and phosphatases in the signal cascade triggered by different stimuli in other steroidogenic tissues is also compared to adrenocortical cell/ACTH and discussed.

Blood cells and endothelial barrier function.

The barrier properties of endothelial cells are critical for the maintenance of water and protein balance between the intravascular and extravascular compartments. An impairment of endothelial barrier function has been implicated in the genesis and/or progression of a variety of pathological conditions, including pulmonary edema, ischemic stroke, neurodegenerative disorders, angioedema, sepsis and cancer. The altered barrier function in these conditions is often linked to the release of soluble mediators from resident cells (e.g., mast cells, macrophages) and/or recruited blood cells. The interaction of the mediators with receptors expressed on the surface of endothelial cells diminishes barrier function either by altering the expression of adhesive proteins in the inter-endothelial junctions, by altering the organization of the cytoskeleton, or both. Reactive oxygen species (ROS), proteolytic enzymes (e.g., matrix metalloproteinase, elastase), oncostatin M, and VEGF are part of a long list of mediators that have been implicated in endothelial barrier failure. In this review, we address the role of blood borne cells, including, neutrophils, lymphocytes, monocytes, and platelets, in the regulation of endothelial barrier function in health and disease. Attention is also devoted to new targets for therapeutic intervention in disease states with morbidity and mortality related to endothelial barrier dysfunction.

Efecto del factor de crecimiento de fibroblastos 21 / Fibroblast growht factor 21 effects over phosphatase SHP-2 expression in Malme-3 cells

Almost 50 percent of Noonan syndrome patients, characterized by short stature, present activating mutations of the citoplasmatic phosphatase SHP-2, which induce hyperactivation of the Ras/MAPK pathway. On the other hand, the fibroblast growth factor 21 (FGF-21), recently suggested as a FGF with “endocrine” function, would affect longitudinal growth inhibiting growth hormone signaling at chondrocytes level. Union and activation of FGF-21 to its receptor is regulated by the co-factor beta Klotho (KLB). Aims: To determine if FGF-21 and/or FGF-21+KLB are able to modify the genetic expression of SHP-2 ina human skin fibroblast cell line (Malme-3). Methods: cells were incubated with or without FGF-21, FGF-21 + KLB. At 12 and 24 hours after induction total RNA was extracted andSHP-2 mRNA levels were determine by quantitative PCR. Expression of GADPH gene was employed for normalization. Results: Incubation with FGF-21 produce a 36 percent (p = < 0,05)increment in SHP-2 expression, which was not modified with KLB co-incubation. Discussion: it is shown by the first time that FGF-21 is able to produce an increase in SHP-2 gene expression in human fibroblast, which was independent of KLB presence...

Síndrome de Noonan / Noonan syndrome

El Síndrome de Noonan fue descrito por Noonan y Ehmke en 1963. La incidencia se ha estimado en 1 de 1000 y 1 de 2500 nacimientos vivos.1 El gen se encuentra localizado en el cromosoma 12q22 y se hereda en forma autosómica dominante y tiene una expresividad muy variable. La principal característica incluye estatura baja, defectos cardiacos, dismorfismo facial entre otros. Estatura La severidad de los síntomas varían mucho en estos pacientes. Lo que no siempre es fácil hacer el diagnóstico en los primeros años, y muchas veces son subdiagnosticados, condición que nos motivo a revisar el caso.

Noonan Syndrome is a relative common autosomic dominant congenital disorder, with an incidence between 1:1,000 and 1:2,500 children worldwide. The gen is in 12q22 chromosome. The principal features include short stature, typical facial dysmorphology and congenital heart disease, among others. The range and severity of features can vary greatly in patients with NS, therefore, establishing a diagnose is difficult. The syndrome is not always identified at an early age, and many times misdiagnosed.

PTK2 and PTPN11 expression in myelodysplastic syndromes

OBJECTIVE: The aim of this study was to evaluate the expression of protein tyrosine kinase 2 and protein tyrosine phosphatase non-receptor type 11, which respectively encode focal adhesion kinase protein and src homology 2 domain-containing protein-tyrosine phosphatase 2, in hematopoietic cells from patients with myelodysplastic syndromes. METHODS: Protein tyrosine kinase 2 and tyrosine phosphatase non-receptor type 11 expressions were analyzed by quantitative polymerase chain reaction in bone marrow cells from patients with myelodysplastic syndromes and healthy donors. RESULTS: Protein tyrosine kinase 2 and tyrosine phosphatase non-receptor type 11 expressions did not significantly differ between normal cells and myelodysplastic cells. CONCLUSIONS: Our data suggest that despite the relevance of focal adhesion kinase and src homology 2 domain-containing protein-tyrosine phosphatase 2 in hematopoietic disorders, their mRNA expression do not significantly differ between total bone marrow cells from patients with myelodysplastic syndromes and healthy donors. .