Transgenic overexpression of 14-3-3 zeta protects hippocampus against endoplasmic reticulum stress and status epilepticus in vivo.

14-3-3 proteins are ubiquitous molecular chaperones that are abundantly expressed in the brain where they regulate cell functions including metabolism, the cell cycle and apoptosis. Brain levels of several 14-3-3 isoforms are altered in diseases of the nervous system, including epilepsy. The 14-3-3 zeta (ζ) isoform has been linked to endoplasmic reticulum (ER) function in neurons, with reduced levels provoking ER stress and increasing vulnerability to excitotoxic injury. Here we report that transgenic overexpression of 14-3-3ζ in mice results in selective changes to the unfolded protein response pathway in the hippocampus, including down-regulation of glucose-regulated proteins 78 and 94, activating transcription factors 4 and 6, and Xbp1 splicing. No differences were found between wild-type mice and transgenic mice for levels of other 14-3-3 isoforms or various other 14-3-3 binding proteins. 14-3-3ζ overexpressing mice were potently protected against cell death caused by intracerebroventricular injection of the ER stressor tunicamycin. 14-3-3ζ overexpressing mice were also potently protected against neuronal death caused by prolonged seizures. These studies demonstrate that increased 14-3-3ζ levels protect against ER stress and seizure-damage despite down-regulation of the unfolded protein response. Delivery of 14-3-3ζ may protect against pathologic changes resulting from prolonged or repeated seizures or where injuries provoke ER stress

Cross-Talk Between JNK/SAPK and ERK/MAPK Pathways: Sustained Activation of JNK Blocks ERK Activation by Mitogenic Factors

Mixed lineage kinases (MLKs) are a family of serine/threonine kinases that function in the SAPK signaling cascade. MLKs activate JNK/SAPK in vivo by directly phosphorylating and activating the JNK kinase SEK-1 (MKK4 and -7). Importantly, the MLK member MLK3/SPRK has been shown recently to be a direct target of ceramide and tumor necrosis factor-α (TNF-α) and to mediate the TNF-α and ceramide-induced JNK activation in Jurkat cells. Here we report that MLK3 can phosphorylate and activate MEK-1 directly in vitro and also can induce MEK phosphorylation on its activation sites in vivo in COS-7 cells. Surprisingly, this induction of MEK phosphorylation does not result in ERK activation in vivo. Rather, in cells expressing active MLK3, ERK becomes resistant to activation by growth factors and mitogens. This restriction in ERK activation requires MLK3 kinase activity, is independent of Raf activation, and is reversed by JNK pathway inhibition either at the level of SEK-1, JNK, or Jun. These results demonstrate that sustained JNK activation uncouples ERK activation from MEK in a manner requiring Jun-mediated gene transcription. This in turn points to the existence of a negative cross-talk relationship between the stress-activated JNK pathway and the mitogen-activated ERK pathway. Thus, our findings imply that some of the biological functions of JNK activators, such as TNF-α and ceramide, may be attributed to their ability to block cell responses to growth and survival factors acting through the ERK/MAPK pathway

AKT and 14-3-3 regulate Notch4 nuclear localization

Members of the Notch family of transmembrane receptors, Notch1-4 in mammals, are involved in the regulation of cell fate decisions and cell proliferation in various organisms. The Notch4 isoform, which is specific to mammals, was originally identified as a viral oncogene in mice, Int3, able to initiate mammary tumors. In humans, Notch4 expression appears to be associated with breast cancer stem cells and endocrine resistance. Following ligand binding, the Notch4 receptor undergoes cleavage at the membrane and the Notch4-intracellular domain (ICD), translocates to the nucleus and regulates gene transcription. Little is known on the mechanisms regulating Notch4-ICD and its nuclear localization. Here, we describe the identification of four distinct AKT phosphorylation sites in human Notch4-ICD and demonstrate that AKT binds Notch4-ICD and phosphorylates all four sites in vitro and in vivo. The phosphorylation in cells is regulated by growth factors and is sensitive to phosphatidyl inositol-3 kinase (PI3K) inhibitors. This phosphorylation generates binding sites to the 14-3-3 regulatory proteins, which are involved in the regulation of nucleocytoplasmic shuttling of target proteins, restricting phosphorylated Notch4-ICD to the cytoplasm. Our findings provide a novel mechanism for Notch4-ICD regulation, suggesting a negative regulatory role for the PI3K-AKT pathway in Notch4 nuclear signaling

Determining new anthropometric markers for screening T2DM in Jaipur, India: A cross sectional study

WHO has estimated expected cases of T2DM to rise to 57.2 million by the year 2025 and 80.9 million by the year 2030. Since past two decades there has been constant marked increase in the prevalence of diabetes in urban population of India with noticeable rise in southern part of India. The Prevalence of T2DM ranges from 10-16 % from region to region. The primary objective of the study was to determine the association between Indices using height, waist, hip, thigh, arm, and wrist circumference (cm) with development of T2DM and compare it to existing markers in test subjects and assessing their feasibility as predictive indicators for the development of T2DM. In a cross-sectional study, a total of 605 subjects were involved in the study which included health centers and health camps in Jaipur, India. The study duration was of 1 years (December 2019 to November 2020). Height-to-waist ratio (HtWR), ABI (Arav Body Index), Thigh to waist ratio (TWR) and Wrist to arm ratio (WAR) was compared to common existing markers such as WHtR, WHR and BMI.&nbsp

Determining new anthropometric markers for screening T2DM in Jaipur, India: A cross sectional study

WHO has estimated expected cases of T2DM to rise to 57.2 million by the year 2025 and 80.9 million by the year 2030. Since past two decades there has been constant marked increase in the prevalence of diabetes in urban population of India with noticeable rise in southern part of India. The Prevalence of T2DM ranges from 10-16 % from region to region.  The primary objective of the study was to determine the association between Indices using height, waist, hip, thigh, arm, and wrist circumference (cm) with development of T2DM and compare it to existing markers in test subjects and assessing their feasibility as predictive indicators for the development of T2DM. In a cross-sectional study, a total of 605 subjects were involved in the study which included health centers and health camps in Jaipur, India. The study duration was of 1 years (December 2019 to November 2020). Height-to-waist ratio (HtWR), ABI (Arav Body Index), Thigh to waist ratio (TWR) and Wrist to arm ratio (WAR) was compared to common existing markers such as WHtR, WHR and BMI.&nbsp

Determining new anthropometric markers for screening T2DM in Jaipur, India: A cross sectional study

WHO has estimated expected cases of T2DM to rise to 57.2 million by the year 2025 and 80.9 million by the year 2030. Since past two decades there has been constant marked increase in the prevalence of diabetes in urban population of India with noticeable rise in southern part of India. The Prevalence of T2DM ranges from 10-16 % from region to region. The primary objective of the study was to determine the association between Indices using height, waist, hip, thigh, arm, and wrist circumference (cm) with development of T2DM and compare it to existing markers in test subjects and assessing their feasibility as predictive indicators for the development of T2DM. In a cross-sectional study, a total of 605 subjects were involved in the study which included health centers and health camps in Jaipur, India. The study duration was of 1 years (December 2019 to November 2020). Height-to-waist ratio (HtWR), ABI (Arav Body Index), Thigh to waist ratio (TWR) and Wrist to arm ratio (WAR) was compared to common existing markers such as WHtR, WHR and BMI.

Disruption of the PHRF1 Tumor Suppressor Network by PML-RARα Drives Acute Promyelocytic Leukemia Pathogenesis

PHRF1 functions as an essential component of the TGF-β tumor suppressor pathway by triggering degradation of the homeodomain repressor factor TGIF. This leads to redistribution of cPML into the cytoplasm, where it coordinates phosphorylation and activation of Smad2 by the TGF-β receptor. In acute promyelocytic leukemia (APL), acquisition of PML-RARα is known to impede critical aspects of TGF-β signaling, including myeloid differentiation. Although these defects are thought to rely on suppression of cPML activity, the mechanisms underlying this phenomenon remain enigmatic. Here, we find that an abnormal function of PML-RARα is to interfere with TGIF breakdown, presumably by competing with PHRF1 for binding to TGIF, culminating in cPML sequestration and inactivation. Enforcing PHRF1 activity is sufficient to restore TGF-β cytostatic signaling in human blasts and suppress APL formation in a mouse model of APL, providing proof-of-concept data that suppression of PHRF1 activity by PML-RARα represents a critical determinant in APL pathogenesis

Significance of 14-3-3 Self-Dimerization for Phosphorylation-dependent Target Binding

14-3-3 proteins via binding serine/threonine-phosphorylated proteins regulate diverse intracellular processes in all eukaryotic organisms. Here, we examine the role of 14-3-3 self-dimerization in target binding, and in the susceptibility of 14-3-3 to undergo phosphorylation. Using a phospho-specific antibody developed against a degenerated mode-1 14-3-3 binding motif (RSxpSxP), we demonstrate that most of the 14-3-3-associated proteins in COS-7 cells are phosphorylated on sites that react with this antibody. The binding of these phosphoproteins depends on 14-3-3 dimerization, inasmuch as proteins associated in vivo with a monomeric 14-3-3 form are not recognized by the phospho-specific antibody. The role of 14-3-3 dimerization in the phosphorylation-dependent target binding is further exemplified with two well-defined 14-3-3 targets, Raf and DAF-16. Raf and DAF-16 can bind both monomeric and dimeric 14-3-3; however, whereas phosphorylation of specific Raf and DAF-16 sites is required for binding to dimeric 14-3-3, binding to monomeric 14-3-3 forms is entirely independent of Raf and DAF-16 phosphorylation. We also find that dimerization diminishes 14-3-3 susceptibility to phosphorylation. These findings establish a significant role of 14-3-3 dimerization in its ability to bind targets in a phosphorylation-dependent manner and point to a mechanism in which 14-3-3 phosphorylation and dimerization counterregulate each other