As a member of the Rab small GTPase family, Rab11a has been shown to be involved in different vesicle trafficking processes. In earlier work we identified Rab11a to be present in GLUT4-containing vesicles after insulin stimulation and showed its involvement in insulin-dependent glucose uptake. However, it remained elusive if Rab11a is directly activated by the insulin signalling cascade and at which step a potential activation occurs. To examine the GTP-loading of Rab11a, we introduced a biotinylated GTP-analog into H9c2-hIR cells, transiently overexpressing HA-tagged Rab11a, and measured its binding to the GTPase after insulin stimulation. We observed that Rab11a is transiently GTP-loaded after insulin stimulation with a 2.3 (+/-0.3) fold activation (n=5), reaching its maximum after 4 min and declining back to basal after additional 2 min. The activation of Rab11a is phosphatidylinositol 3-kinase (PI3-kinase) dependent and downstream of Akt, as shown by in vitro knockdown of this kinase. These data show that Rab11a is directly activated by insulin and represents an element of the GLUT4 trafficking machinery.
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http://dx.doi.org/10.1016/j.cellsig.2006.10.008 | DOI Listing |
Nutrients
January 2025
Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University, 1 Hikarigaoka, Fukushima City 960-1295, Fukushima, Japan.
(1) Background: It has been reported that people affected by COVID-19, an infectious disease caused by SARS-CoV-2, suffer from various diseases, after infection. One of the most serious problems is the increased risk of developing diabetes after COVID-19 infection. However, a treatment for post-COVID-19 infection diabetes has not yet been established.
View Article and Find Full Text PDFJ Clin Med
January 2025
The Experts Group on Inositol in Basic and Clinical Research, and on PCOS (EGOI-PCOS), 00161 Rome, Italy.
Myo-inositol plays a vital role in human health, functioning as a second messenger of FSH and facilitating the transport of glucose into the cell. Consequently, myo-inositol is regularly utilized in the treatment of polycystic ovary syndrome (PCOS), wherein it acts upon metabolic factors, improving insulin sensitivity and reducing total androgen levels. Patients with PCOS frequently suffer from infertility; thus, the use of myo-inositol has been explored in improving assistive reproductive technique (ART) procedures.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Departamento de Biomedicina Cardiovascular, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City 14080, Mexico.
Diets rich in carbohydrate and saturated fat contents, when combined with a sedentary lifestyle, contribute to the development of obesity and metabolic syndrome (MetS), which subsequently increase palmitic acid (PA) levels. At high concentrations, PA induces lipotoxicity through several mechanisms involving endoplasmic reticulum (ER) stress, mitochondrial dysfunction, inflammation and cell death. Nevertheless, there are endogenous strategies to mitigate PA-induced lipotoxicity through its unsaturation and elongation and its channeling and storage in lipid droplets (LDs), which plays a crucial role in sequestering oxidized lipids, thereby reducing oxidative damage to lipid membranes.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Research Center for Non-Infectious Diseases and Environmental Health Sciences, Research Institute for Health Sciences, Chiang Mai University, Chiang Mai 50200, Thailand.
Recently, toxicological and epidemiological research has provided strong support for the unfavorable effects of bisphenol-A (BPA, 2,2'-bis(4-hydroxyphenyl) propane) on myogenesis and its underlying mechanisms. Researchers have therefore been looking for new strategies to prevent or mitigate these injurious effects of BPA on the human body. It has been found that plant extracts may act as potential therapeutic agents or functional foods, preventing human diseases caused by BPA.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Endocrinology Unit, Department of Internal Medicine and Medical Specialties, School of Medical and Pharmaceutical Sciences, University of Genova, 16132 Genova, Italy.
Acromegaly is a rare endocrine disorder caused by excessive growth hormone (GH) production, due, in the vast majority of cases, to the presence of a GH-secreting pituitary tumour. The chronic elevation of GH and the resulting high circulating levels of insulin-like growth factor-1 (IGF-1) cause the characteristic tissue overgrowth and a number of associated comorbidities, including several metabolic changes, such as glucose intolerance and overt diabetes mellitus (DM). Elevated GH concentrations directly attenuate insulin signalling and stimulate lipolysis, decreasing glucose uptake in peripheral tissues, thus leading to the development of impaired glucose tolerance and DM.
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