Differential proteomic analysis of the anti-proliferative effect of glucocorticoid hormones in ST1 rat glioma cells

hnRNP A/B Proteins: An Encyclopedic Assessment of Their Roles in Homeostasis and Disease

The hnRNP A/B family of proteins is canonically central to cellular RNA metabolism, but due to their highly conserved nature, the functional differences between hnRNP A1, A2/B1, A0, and A3 are often overlooked. In this review, we explore and identify the shared and disparate homeostatic and disease-related functions of the hnRNP A/B family proteins, highlighting areas where the proteins have not been clearly differentiated. Herein, we provide a comprehensive assembly of the literature on these proteins. We find that there are critical gaps in our grasp of A/B proteins' alternative splice isoforms, structures, regulation, and tissue and cell-type-specific functions, and propose that future mechanistic research integrating multiple A/B proteins will significantly improve our understanding of how this essential protein family contributes to cell homeostasis and disease.

Proteomic analysis of the nuclear phosphorylated proteins in dairy cow mammary epithelial cells treated with estrogen

Estrogen regulates a variety of physiological processes, including mammary gland growth, morphogenesis of the mammary gland, proliferation and differentiation, and elevating the expression of milk proteins. Many nuclear phosphorylated proteins such as pStat5 and mTOR regulate milk protein synthesis. But the detail of milk protein synthesis controlled at the transcript level and posttranslational level is not well-known. To contribute to the understanding of the molecular mechanism underlying estrogen action on the dairy cow mammary epithelial cells (DCMECs), nuclear phosphorylated proteins regulated by estrogen in DCMECs were identified. Two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization/time of flight mass spectrometry were used to identify the changes of nuclear phosphorylated proteins in DCMECs treated with estrogen. Seven proteins were identified differentially up-expressed in DCMECs after 24-h estrogen exposure: including glycyl-tRNA synthetase, previously reported in milk protein synthesis of DCMECs, belonging to the class-II aminoacyl-tRNA synthetase family; proteins involved in other cellular functions, such as translation initiation factors, GTP-binding nuclear proteins, heat-shock proteins, and proteins belonging to ubiquitin-proteasome system. This screening reveals that estrogen influences the levels of nuclear phosphorylated proteins of DCMECs which opens new avenue for the study of the molecular mechanism linking to milk synthesis.

Overexpression of Nrp/b (nuclear restrict protein in brain) suppresses the malignant phenotype in the C6/ST1 glioma cell line

Upon searching for glucocorticoid-regulated cDNA sequences associated with the transformed to normal phenotypic reversion of C6/ST1 rat glioma cells, we identified Nrp/b (nuclear restrict protein in brain) as a novel rat gene. Here we report on the identification and functional characterization of the complete sequence encoding the rat NRP/B protein. The cloned cDNA presented a 1767 nucleotides open-reading frame encoding a 589 amino acids residues sequence containing a BTB/POZ (broad complex Tramtrack bric-a-brac/Pox virus and zinc finger) domain in its N-terminal region and kelch motifs in its C-terminal region. Sequence analysis indicates that the rat Nrp/b displays a high level of identity with the equivalent gene orthologs from other organisms. Among rat tissues, Nrp/b expression is more pronounced in brain tissue. We show that overexpression of the Nrp/b cDNA in C6/ST1 cells suppresses anchorage independence in vitro and tumorigenicity in vivo, altering their malignant nature towards a more benign phenotype. Therefore, Nrp/b may be postulated as a novel tumor suppressor gene, with possible relevance for glioblastoma therapy.

Nutritional manipulation between early to mid-gestation: effects on uncoupling protein-2, glucocorticoid sensitivity, IGF-I receptor and cell proliferation but not apoptosis in the ovine placenta

In sheep, modest maternal nutrient restriction (NR) over the period of rapid placental growth restricts placentome growth and results in offspring in which glucocorticoid action is enhanced. Therefore, this study investigated the placental effects of early to mid-gestational NR on glucocorticoid receptor (GR), 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2), uncoupling protein-2 (UCP2), and IGF type-I receptor (IGF-IR) mRNA abundance together with cell proliferation and apoptosis as determined histologically, and the mitochondrial proteins voltage-dependent anion channel and cytochromecthat are involved in apoptosis. Placenta was sampled at 80 and 140 days gestation (dGA; term ~147 dGA). NR was imposed between 28 and 80 days gestation when control and nutrient-restricted groups consumed 150 or 60% respectively of their total metabolizable energy requirements. All mothers were then fed to requirements up to term. Total fetal placentome weights were decreased by NR at 80 dGA but were heavier at 140 dGA following 60 days of nutritional rehabilitation. GR and UCP2 mRNA abundance increased whilst 11βHSD2 mRNA decreased with gestational age. NR persistently up-regulated GR and UCP2 mRNA abundance. 11βHSD2 mRNA was reduced by NR at 80 dGA but increased near to term. IGF-IRmRNA abundance was only decreased at 80 dGA. Placental apoptosis and mitochondrial protein abundance were unaffected by NR, whereas cell proliferation was markedly reduced. In conclusion, placental UCP2 and local glucocorticoid action are affected by the gestational nutritional status and may result in the offspring showing enhanced glucocorticoid sensitivity, thereby predisposing them to disease in later life.