dictyNews Electronic Edition Volume 42, number 13 May 6, 2016 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. Follow dictyBase on twitter: http://twitter.com/dictybase ========= Abstracts ========= Oral administration of Dictyostelium differentiation-inducing factor 1 lowers blood glucose levels in streptozotocin-induced diabetic rats Ritsuko Kawaharada, Akio Nakamura, Katsunori Takahashi, Haruhisa Kikuchi, Yoshiteru Oshima, Yuzuru Kubohara* *Graduate School of Health and Sports Science, Juntendo University, Inzai City, 270-1695, Japan. Life Sciences, in press Aims: Differentiation-inducing factor 1 (DIF-1), originally discovered in the cellular slime mold Dictyostelium discoideum, and its derivatives possess pharmacological activities, such as the promotion of glucose uptake in non-transformed mammalian cells in vitro. Accordingly, DIFs are considered promising lead candidates for novel anti-diabetic drugs. The aim of this study was to assess the anti-diabetic and toxic effects of DIF-1 in mouse 3T3-L1 fibroblast cells in vitro and in diabetic rats in vivo. Main methods: We investigated the in vitro effects of DIF-1 and DIF-1(3M), a derivative of DIF-1, on glucose metabolism in 3T3-L1 cells by using capillary electrophoresis time-of-flight mass spectrometry (CE-TOF-MS). We also examined the effects of DIF-1 on blood glucose levels in streptozotocin (STZ)-induced rats. Key findings: CE-TOF-MS revealed that 20 microM DIF-1 and 20 microM DIF-1(3M) promoted glucose uptake and metabolism in 3T3-L1 cells. Oral administration of DIF-1 (30 mg/kg) significantly lowered basal blood glucose levels in STZ-treated rats and promoted a decrease in blood glucose levels after oral glucose loading (2.5 g/kg) in the rats. In addition, daily oral administration of DIF-1 (30 mg/kg/day) for 1 wk significantly lowered the blood glucose levels in STZ-treated rats but did not affect their body weight and caused only minor alterations in the levels of other blood analytes. Significance: These results indicate that DIF-1 may be a good lead compound for the development of anti-diabetic drugs. submitted by: Yuzuru Kubohara [ykuboha@juntendo.ac.jp] ——————————————————————————————————————— Quantitative imaging of Rac1 activity in Dictyostelium cells with a fluorescently labelled GTPase-binding domain from DPAKa kinase Maja Marinović, Marko Šoštar, Vedrana Filić, Vlatka Antolović, Igor Weber Histochemistry and Cell Biology, http://link.springer.com/article/10.1007/s00418-016-1440-9 Small Rho GTPases are major regulators of the actin cytoskeleton dynamics in eukaryotic cells. Sophisticated tools used to investigate their activity in living cells include probes based on fluorescence resonance energy transfer (FRET), bimolecular fluorescence complementation, and photoactivation. However, such methods are of limited use in quickly migrating cells due to a short time available for image acquisition leading to a low signal-to-noise ratio. Attempts to remedy this effect by increasing the intensity of illumination are restricted by photobleaching of probes and the cell photosensitivity. Here we present design and characterization of a new fluorescent probe that selectively binds to active form of Rac1 GTPases, and demonstrate its superior properties for imaging in highly motile Dictyostelium cells. The probe is based on the GTPase-binding domain (GBD) from DPAKa kinase and was selected on the basis of yeast two-hybrid screen, GST pull-down assay and FRET measurements by fluorescence lifetime imaging microscopy. DPAKa(GBD) probe binds specifically to GTP-bound Rac1 at the cell membrane and features a low cytoplasmic background. The main advantage of DPAKa(GBD) in comparison with similar probes is its finely graded intensity distribution along the entire plasma membrane, which enables quantitative measurements of the Rac1 activity in different parts of the membrane. Finally, expression of DPAKa(GBD) induces no adverse effects on cell growth, motility and cytokinesis. submitted by: Maja Marinović [Maja.Marinovic@irb.hr] ============================================================== [End dictyNews, volume 42, number 13]