An epidemic of metabolic disorders such as obesity and diabetes is rising dramatically. Using natural products as potential preventive and therapeutic interventions for these disorders has drawn worldwide attention. Rosemary has been shown to lower blood glucose and cholesterol levels and mitigate weight gain in several in vivo studies. However, the mechanisms are essentially unknown. We investigated the effects of rosemary extract on metabolism and demonstrated that rosemary extract significantly increased glucose consumption in HepG2 cells. The phosphorylation of AMP-activated protein kinase (AMPK) and its substrate, acetyl-CoA carboxylase (ACC), was increased by rosemary extract. Rosemary extract also transcriptionally regulated the genes involved in metabolism, including SIRT1, PPARγ coactivator 1α (PGC1α), glucose-6-phosphatase (G6Pase), ACC, and low-density lipoprotein receptor (LDLR). Furthermore, the PPARγ-specific antagonist GW9662 diminished rosemary's effects on glucose consumption. Overall, our study suggested that rosemary potentially increases liver glycolysis and fatty acid oxidation by activating AMPK and PPAR pathways.

Iron-sulfur proteins play an essential role in many biologic processes. Hence, understanding their assembly is an important goal. In Escherichia coli, the protein IscA is a product of the isc (iron-sulfur cluster) operon and functions in the iron-sulfur cluster assembly pathway in this organism. IscA is conserved in evolution, but its function in mammalian cells is not known. Here, we provide evidence for a role for a human homologue of IscA, named IscA1, in iron-sulfur protein biogenesis. We observe that small interfering RNA knockdown of IscA1 in HeLa cells leads to decreased activity of two mitochondrial iron-sulfur enzymes, succinate dehydrogenase and mitochondrial aconitase, as well as a cytosolic iron-sulfur enzyme, cytosolic aconitase. IscA1 is observed both in cytosolic and mitochondrial fractions. We find that IscA1 interacts with IOP1 (iron-only hydrogenase-like protein 1)/NARFL (nuclear prelamin A recognition factor-like), a cytosolic protein that plays a role in the cytosolic iron-sulfur protein assembly pathway. We therefore propose that human IscA1 plays an important role in both mitochondrial and cytosolic iron-sulfur cluster biogenesis, and a notable component of the latter is the interaction between IscA1 and IOP1.Iron-sulfur proteins play essential roles in pathways that include the Krebs cycle, oxidative phosphorylation, gene regulation, and purine metabolism (1, 2). Their assembly presents particular challenges in that iron is readily oxidized and can generate free radicals. Hence, there are specific pathways that participate in the assembly of iron-sulfur clusters. In bacteria such as Escherichia coli, there is a pathway dedicated to the assembly of iron-sulfur clusters (3). The isc operon is the central genetic locus for this pathway, and it contains genes that encode for the proteins that include IscS, IscU, and IscA. The key elements of this pathway include a mechanism for obtaining sulfur through the enzymatic activity of a cysteine desulfurase, a mechanism for combining sulfur with iron on scaffold proteins, and a means for delivery of the resultant iron-sulfur clusters to target apoproteins. It appears that these key elements have been conserved through evolution. Thus, the E. coli cysteine desulfurase IscS has homologues in Saccharomyces cerevisiae and mammalian cells, indicative of a central conserved function. Moreover, homologues of IscU and IscA also exist in yeast and mammalian cells. The exact function of these is less certain. For example, IscU has been proposed to be a scaffold of iron-sulfur cluster assembly in E. coli, S. cerevisiae, and mammals (4 -6). IscA has been proposed to serve as a scaffold for delivering iron-sulfur clusters to select target proteins in E. coli and S. cerevisiae or, alternatively, as an iron donor in E. coli (7-10); its role in mammalian cells is not known.In eukaryotic cells, the situation is made more complex by the necessity of having to assemble both mitochondrial and cytosolic iron-sulfur clusters. In S. cerevisiae, there are proteins dedicated...

The IB kinase (IKK) complex consists of the catalytic subunits IKK␣ and IKK␤ and a regulatory subunit, IKK␥/NEMO. Even though IKK␣ and IKK␤ share significant sequence similarity, they have distinct biological roles. It has been demonstrated that IKKs are involved in regulating the proliferation of both normal and tumor cells, although the mechanisms by which they function in this process remain to be better defined. In this study, we demonstrate that IKK␣, but not IKK␤, is important for estrogen-induced cell cycle progression by regulating the transcription of the E2F1 gene as well as other E2F1-responsive genes, including thymidine kinase 1, proliferating cell nuclear antigen, cyclin E, and cdc25A. The role of IKK␣ in regulating E2F1 was not the result of reduced levels of cyclin D1, as overexpression of this gene could not overcome the effects of IKK␣ knock-down. Furthermore, estrogen treatment increased the association of endogenous IKK␣ and E2F1, and this interaction occurred on promoters bound by E2F1. IKK␣ also potentiated the ability of p300/CBP-associated factor to acetylate E2F1. Taken together, these data suggest a novel mechanism by which IKK␣ can influence estrogen-mediated cell cycle progression through its regulation of E2F1.The mammalian cell cycle is controlled by a series of highly regulated processes, and its dysregulation is frequently associated with growth abnormalities including the development of cancer (reviewed in Refs. 1-3). The Rb/E2F pathway, which governs the G 1 to S phase transition, is one of the most important pathways that regulate the cell cycle. A major function of Rb is to sequester E2F family transcription factors and repress E2F-regulated promoters (4). The Rb family of proteins, which includes Rb, p107, and p130, forms different complexes with the E2F family members (5, 6). In the early G 1 phase, the activated cyclin D-CDK4 complex phosphorylates Rb, leading to its degradation and the release of E2F. This process in turn activates the expression of cyclin E and other genes required for DNA replication (1). Cyclin E then binds to CDK2 to further phosphorylate Rb, thus forming a positive feedback loop to promote the entry of cells into the S phase. Abnormalities in this pathway and in the p53 tumor suppressor pathway are seen in almost all human tumors (4, 7).The E2F family, which is critical for cell cycle progression from the late G 1 into S phase, comprises seven members, designated E2F1-7, and can be further classified into three subfamilies based on sequence homology and function: E2F1-3, E2F4 -5, and E2F6 -7 (5, 6, 8).Although E2F1-3 are positive regulators of gene expression, E2F4 -5 are transcriptional repressors when bound to Rb family proteins, and E2F6 functions as a transcriptional repressor given the fact that it lacks a transactivation domain (1, 5). The E2F family members form complexes with the DP proteins (DP-1 and DP-2) to activate the transcription of genes important for DNA replication (such as thymidine kinase 1 (TK1), 3 proliferating cell nuclear antig...

The IKK complex includes two catalytic components, IKKalpha and IKKbeta, in addition to the scaffold protein IKKgamma/NEMO. Even though IKKalpha and IKKbeta share significant sequence homology, they have distinct biological roles with IKKbeta regulates the classical pathway of NF-kappaB activation and IKKalpha regulates the alternative pathways. In addition, it has been shown that the IKKs regulate the proliferation of both normal and tumor cells; however, the mechanisms by which the IKKs regulate the cell cycle remain to be further defined. Here, we demonstrate that IKKalpha, but not IKKbeta, has role in regulating the M phase of the cell cycle. IKKalpha siRNA knock -down resulted in increased numbers of cells in the G(2)/M phase of the cell cycle as compared to control and IKKbeta siRNA transfected HeLa cells. This effect was associated with upregulation of cyclin B1 and Plk1 protein levels and increased histone H3 phosphorylation, consistent with a potential role of IKKalpha in the regulation of M phase regulatory factors. IKKalpha was found to be associated with Aurora A in the centrosome and regulate Aurora A phosphorylation at threonine residue 288, a site which is important in modulating its kinase activity. Taken together, these data provide the evidence that IKKalpha regulates the M phase of the cell cycle by modulating Aurora A phosphorylation and activation leading to the regulation of the M phase of the cell cycle.

A series of N-(3-((1H-pyrazolo[3,4-b]pyridin-5-yl)ethynyl)benzenesulfonamides were designed as the first class of highly selective ZAK inhibitors. The representative compound 3h strongly inhibits the kinase activity of ZAK with an IC of 3.3 nM and dose-dependently suppresses the activation of ZAK downstream signals in vitro and in vivo, while it is significantly less potent for the majority of 403 nonmutated kinases evaluated. Compound 3h also exhibits orally therapeutic effects on cardiac hypertrophy in a spontaneous hypertensive rat model.