ABSTRACT
Las investigaciones etnofarmacológicas que estamos llevando a cabo desde hace varios años en la selva del Perú nos ha permitido plantear la hipótesis que las plantas utilizadas por los nativos para pigmentar su cuerpo, también pueden ser utilizadas para pigmentar la piel de los pollos de carne y la yema del huevo cuando son utilizdos por vía interna. Después de un adecuado screening hemos seleccionado algunas plantas que han demostrado in vivo estas propiedades (efectividad). No se trata de la Curcuma longa (palillo), Bixa orellana (achiote), tampoco de la Tagetes sp. (marigold). Se trata de especies que además, se usan ampliamente por sus propiedades medicinales (seguridad) y que contienen componentes bioactivos con estructuras químicas hidro y liposolubles lo cual hace que su efecto en la piel del ave se aprecie en pocos días (economía). Todo lo cual es muy ventajoso en comparación con las xantofilas que se vienen usando en la avicultura mundial. Los ensayos se estan realizando en la costa, sierra y selva con resultados muy alentadores; sin embargo, el no contar con un laboratorio adecuadamente equipado está dificultando el desarrollo de estos nuevos pigmentantes. Le correspode a la empresa privada involucrarse en esta iniciativa científica para poder acceder con ventaja competitiva a un gran mercado que tiene crecimiento sostenido.
Subject(s)
Birds , Amazonian Ecosystem , Pigments, BiologicalABSTRACT
Pim-1, an oncogene product of serine/threonine kinase, has been found to play roles in apoptosis induction/suppression, cell-cycle progression and transcriptional regulation by phosphorylating the target proteins involved in these processes. The target proteins phosphorylated by Pim-1, including p100, Cdc25A, PAP-1 and heterochromatin protein 1, have been identified. The precise functions of Pim-1, however, are still poorly understood. In this study, we identified tumor necrosis factor receptor-associated factor 4-associated factor 2/sorting nexin 6 (TFAF2/SNX6) as a Pim-1-binding protein, and we found that TFAF2/SNX6 was phosphorylated and translocated from the cytoplasm to nucleus by Pim-1. This translocation of the protein was not affected by Pim-1-dependent phosphorylation. Since sorting nexins, including TFAF2/SNX6, have been reported to be located in the cytoplasm or membrane by association with several receptors of tyrosine- or serine/threonine-kinase, this is the first report of TFAF2/SNX6 being located in the nucleus after binding to Pim-1.
Subject(s)
Carrier Proteins/metabolism , Cell Nucleus/metabolism , Cytoplasm/metabolism , Protein Serine-Threonine Kinases/physiology , Proteins/metabolism , Proto-Oncogene Proteins/physiology , Vesicular Transport Proteins , Cell Line , Humans , Molecular Sequence Data , Pancreatitis-Associated Proteins , Protein Transport , Proto-Oncogene Proteins c-pim-1 , TNF Receptor-Associated Factor 4 , Tumor Necrosis Factor Receptor-Associated Peptides and ProteinsABSTRACT
Protooncogene, pim-1, has been reported to be a predisposition for lymphomagenesis along with myc, and its protein product, Pim-1, has been shown to be a serine/threonine protein kinase, whose activity is involved in proliferation and differentiation of blood cells. The signal transduction pathways neither to nor from Pim-1, however, have been clarified. We have cloned a cDNA encoding a novel Pim-1 binding protein, PAP-1, comprising 213 amino acids with a basic amino-acid cluster near the C-terminus. PAP-1 was colocalized with Pim-1 in human HeLa cell nuclei. The in vitro binding assays using GST fusion proteins of the wild-type and various deletion mutants revealed that the whole molecule of Pim-1 is required for the binding activity to PAP-1 and that Pim-1 binds to the region from amino-acid numbers 1-147 of PAP-1, or to two segments in the region. The association of PAP-1 with Pim-1 was also shown in vivo in transfected cells. Furthermore, PAP-1 was phosphorylated in vitro by Pim-1, but not a kinase-negative Pim-1 mutant. The two serine residues of PAP-1 at amino acids 204 and 206 near the C-terminus were phosphorylated by Pim-1. PAP-1 is thus thought to be a target protein for Pim-1 kinase.
Subject(s)
Annexin A5/metabolism , Proto-Oncogene Proteins/metabolism , Amino Acid Sequence , Animals , Base Sequence , Binding Sites , COS Cells , Cloning, Molecular , Humans , Jurkat Cells , Kinetics , Molecular Sequence Data , Pancreatitis-Associated Proteins , Phosphorylation , Protein Serine-Threonine Kinases/metabolism , Proto-Oncogene Proteins/chemistry , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins c-pim-1 , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Sequence Alignment , Sequence Homology, Amino Acid , Substrate Specificity , U937 CellsABSTRACT
Pim-1, a protooncogene product, is a serine/threonine kinase and is thought to play a role in signal transduction in blood cells. Few phosphorylated target proteins for Pim-1, however, have been identified. In the present study, two-hybrid screening to clone cDNAs encoding proteins binding to Pim-1 was carried out, and a cDNA for heterochromatin protein 1gamma (HP1gamma) was obtained. Binding assays both in yeast and in vitro pull-down using the purified HP1gamma and Pim-1 expressed in Escherichia coli showed that Pim-1 directly bound to the chromo shadow domain of HP1gamma. HP1gamma was also associated with Pim-1 in human HeLa cells and the serine clusters located at the center of HP1gamma were phosphorylated by Pim-1 in vitro. Furthermore, a transcription repression activity of HP1gamma was further stimulated by the deletion of the serine clusters targeted by Pim-1. These results suggest that Pim-1 affects the structure or silencing of chromatin by phosphorylating HP1.
