Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The GTPase dynamin is involved in endocytosis in many cell types, as first revealed by temperature-sensitive paralytic mutations in the Drosophila dynamin gene, shibire (shi), which disrupt synaptic vesicle endocytosis and deplete synaptic terminals of vesicles. Here we report that shi synapses exhibit a fast synaptic fatigue phenotype within 20 ms of repetitive stimulation, which cannot be explained by vesicle depletion, as we confirmed by electron microscopy. These results suggest that, in addition to its well-characterized role in synaptic vesicle recycling, dynamin may be required for short-term maintenance of the readily releasable pool of synaptic vesicles.
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PMID:Fast synaptic fatigue in shibire mutants reveals a rapid requirement for dynamin in synaptic vesicle membrane trafficking. 1096 13

Chronic fatigue syndrome (CFS) is a clinically defined condition characterized by long-lasting disabling fatigue. Because of the unknown mechanism underlying this syndrome, there still is no specific biomarker for objective assessment of the pathological fatigue. We have compared gene expression profiles in peripheral blood between 11 drug-free patients with CFS and age- and sex-matched healthy subjects using a custom microarray carrying complementary DNA probes for 1,467 stress-responsive genes. We identified 12 genes whose mRNA levels were changed significantly in CFS patients. Of these 12 genes, quantitative real-time PCR validated the changes in 9 genes encoding granzyme in activated T or natural killer cells (GZMA), energy regulators (ATP5J2, COX5B, and DBI), proteasome subunits (PSMA3 and PSMA4), putative protein kinase c inhibitor (HINT ), GTPase (ARHC), and signal transducers and activators of transcription 5A (STAT5A). Next, we performed the same microarray analysis on 3 additional CFS patients and 20 other patients with the chief complaint of long-lasting fatigue related to other disorders (non-CFS patients) and found that the relative mRNA expression of 9 genes classified 79% (11/14) of CFS and 85% (17/20) of the non-CFS patients. Finally, real-time PCR measurements of the levels of the 9 involved mRNAs were done in another group of 18 CFS and 12 non-CFS patients. The expression pattern correctly classified 94% (17/18) of CFS and 92% (11/12) of non-CFS patients. Our results suggest that the defined gene cluster (9 genes) may be useful for detecting pathological responses in CFS patients and for differential diagnosis of this syndrome.
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PMID:Identification of marker genes for differential diagnosis of chronic fatigue syndrome. 1859 70

Mitochondria are dynamic subcellular organelles that convert nutrient intermediates into readily available energy equivalents. Optimal mitochondrial function is ensured by a highly evolved quality control system, coordinated by protein machinery that regulates a process of continual fusion and fission. In this work, we provide in vivo evidence that the ATP-independent metalloprotease OMA1 plays an essential role in the proteolytic inactivation of the dynamin-related GTPase OPA1 (optic atrophy 1). We also show that OMA1 deficiency causes a profound perturbation of the mitochondrial fusion-fission equilibrium that has important implications for metabolic homeostasis. Thus, ablation of OMA1 in mice results in marked transcriptional changes in genes of lipid and glucose metabolic pathways and substantial alterations in circulating blood parameters. Additionally, Oma1-mutant mice exhibit an increase in body weight due to increased adipose mass, hepatic steatosis, decreased energy expenditure and impaired thermogenenesis. These alterations are especially significant under metabolic stress conditions, indicating that an intact OMA1-OPA1 system is essential for developing the appropriate adaptive response to different metabolic stressors such as a high-fat diet or cold-shock. This study provides the first description of an unexpected role in energy metabolism for the metalloprotease OMA1 and reinforces the importance of mitochondrial quality control for normal metabolic function.
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PMID:Loss of mitochondrial protease OMA1 alters processing of the GTPase OPA1 and causes obesity and defective thermogenesis in mice. 2243 42

The oncogenic kinase PAK4 was recently found to be involved in the regulation of the G1 phase and the G2/M transition of the cell cycle. We have also identified that PAK4 regulates Ran GTPase activity during mitosis. Here, we show that after entering mitosis, PAK4-depleted cells maintain a prolonged metaphase-like state. In these cells, chromosome congression to the metaphase plate occurs with normal kinetics but is followed by an extended period during which membrane blebbing and spindle rotation are observed. These bipolar PAK4-depleted metaphase-like spindles have a defective astral microtubule (MT) network and are not centered in the cell but are in close contact with the cell cortex. As the metaphase-like state persists, centrosome fragmentation occurs, chromosomes scatter from the metaphase plate and move toward the spindle poles with an active spindle assembly checkpoint, a phenotype that is reminiscent of cohesion fatigue. PAK4 also regulates the acto-myosin cytoskeleton and we report that PAK4 depletion results in the induction of cortical membrane blebbing during prometaphase arrest. However, we show that membrane blebs, which are strongly enriched in phospho-cofilin, are not responsible for the poor anchoring of the spindle. As PAK4 depletion interferes with the localization of components of the dynein/dynactin complexes at the kinetochores and on the astral MTs, we propose that loss of PAK4 could induce a change in the activities of motor proteins.
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PMID:P21-activated kinase 4 (PAK4) is required for metaphase spindle positioning and anchoring. 2296 Jul 42

McArdle disease is caused by an inherited deficiency of the enzyme myophosphorylase, resulting in exercise intolerance from childhood and acute crises of early fatigue and contractures. In severe cases, these manifestations can be accompanied by rhabdomyolysis, myoglobinuria, and fatal renal failure. Diagnosis of McArdle disease is based on clinical diagnostic tests, together with an absence of myophosphorylase activity in skeletal muscle biopsies and genetic analysis of the myophosphorylase-encoding gene, PYGM. The recently reported association between myophosphorylase and Rac1 GTPase in a T lymphocyte cell line prompted us to study myophosphorylase expression in white blood cells (WBCs) from 20 healthy donors and 30 McArdle patients by flow cytometry using a fluorescent-labeled PYGM antibody. We found that T lymphocytes expressed myophosphorylase in healthy donors, but expression was significantly lower in McArdle patients (p<0.001). PYGM mRNA levels were also lower in white blood cells from McArdle patients. Nevertheless, in 13% of patients (who were either heterozygotes or homozygotes for the most common PYGM pathogenic mutation among Caucasians (p.R50X)), the percentage of myophosphorylase-positive white blood cells was not different compared with the control group. Our findings suggest that analysis of myophosphorylase expression in white blood cells might be a useful, less-invasive, complementary test for diagnosing McArdle disease.
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PMID:PYGM expression analysis in white blood cells: a complementary tool for diagnosing McArdle disease? 2524 Apr 6