A role of nitrite reductase (NirBD) for NO homeostatic regulation in Streptomyces coelicolor A3(2).

Although nitric oxide (NO) is an important signaling molecule in bacteria and higher organisms, excessive intracellular NO is highly reactive and dangerous. Therefore, living cells need strict regulation systems for cellular NO homeostasis. Recently, we discovered that Streptomyces coelicolor A3(2) retains the nitrogen oxide cycle (NO→NO→NO→NO) and nitrite removal system.

Nitrogen oxide cycle regulates nitric oxide levels and bacterial cell signaling.

Nitric oxide (NO) signaling controls various metabolic pathways in bacteria and higher eukaryotes. Cellular enzymes synthesize and detoxify NO; however, a mechanism that controls its cellular homeostasis has not been identified. Here, we found a nitrogen oxide cycle involving nitrate reductase (Nar) and the NO dioxygenase flavohemoglobin (Fhb), that facilitate inter-conversion of nitrate, nitrite, and NO in the actinobacterium Streptomyces coelicolor.

Impacts of age on plasma monoamine metabolite concentrations in a large cohort of healthy individuals.

The measurement of plasma concentrations of monoamine metabolites is a useful method for inferring the dynamics of monoamine metabolites in the brain. To clarify effects of age and sex on plasma monoamine metabolites levels, we used high-performance liquid chromatography to measure plasma levels of homovanillic acid (HVA), free and total 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) in healthy men and women of various ages (n=214). In all plasma monoamine metabolites, there were significant differences across the age groups, and multiple comparisons revealed that older subjects had higher levels than younger subjects.

Prevention of apoptosis by mitochondrial phosphatase PGAM5 in the mushroom body is crucial for heat shock resistance in Drosophila melanogaster.

The heat shock (HS) response is essential for survival of all organisms. Although the machinery of the HS response has been extensively investigated at the cellular level, it is poorly understood at the level of the organism. Here, we show the crucial role of the mushroom body (MB) in the HS response in Drosophila.

p38 MAPKs regulate the expression of genes in the dopamine synthesis pathway through phosphorylation of NR4A nuclear receptors.

In Drosophila, the melanization reaction is an important defense mechanism against injury and invasion of microorganisms. Drosophila tyrosine hydroxylase (TH, also known as Pale) and dopa decarboxylase (Ddc), key enzymes in the dopamine synthesis pathway, underlie the melanin synthesis by providing the melanin precursors dopa and dopamine, respectively. It has been shown that expression of Drosophila TH and Ddc is induced in various physiological and pathological conditions, including bacterial challenge; however, the mechanism involved has not been fully elucidated.

Mitochondrial phosphoglycerate mutase 5 uses alternate catalytic activity as a protein serine/threonine phosphatase to activate ASK1.

Phosphoglycerate mutase (PGAM) is an enzyme of intermediary metabolism that converts 3-phosphoglycerate to 2-phosphoglycerate in glycolysis. Here, we discovered PGAM5 that is anchored in the mitochondrial membrane lacks PGAM activity and instead associates with the MAP kinase kinase kinase ASK1 and acts as a specific protein Ser/Thr phosphatase that activates ASK1 by dephosphorylation of inhibitory sites. Mutation of an active site His-105 in PGAM5 abolished phosphatase activity with ASK1 and phospho-Thr peptides as substrates.