biostudies-literatureLovelace MDNIDDK NIH HHS1066-1078https://www.ebi.ac.uk/biostudies/studies/S-EPMC5391183biostudies-literatureUnknown28(8)RhoGTPases are important regulators of the cell cytoskeleton, controlling cell shape, migration and proliferation. Previously we showed that ARHGAP18 in endothelial cells is important in cell junctions. Here we show, using structured illumination microscopy (SIM), ground-state depletion (GSD), and total internal reflection fluorescence microscopy (TIRF) that a proportion of ARHGAP18 localizes to microtubules in endothelial cells, as well as in nonendothelial cells, an association confirmed biochemically. In endothelial cells, some ARHGAP18 puncta also colocalized to Weibel-Palade bodies on the microtubules. Depletion of ARHGAP18 by small interfering RNA or analysis of endothelial cells isolated from ARHGAP18-knockout mice showed microtubule destabilization, as evidenced by altered morpholoMolecular biology of the cellThe RhoGAP protein ARHGAP18/SENEX localizes to microtubules and regulates their stability in endothelial cells.PMC5391183R01 DK107309Lovelace MDZhao YParker AColeman PRGamble JRKavallaris MBertolino PChang GHPowter EEVadas MAMcCaughan GLay AJMcGrath APJormakka MHunter JfalseThe RhoGAP protein ARHGAP18/SENEX localizes to microtubules and regulates their stability in endothelial cells.RhoGTPases are important regulators of the cell cytoskeleton, controlling cell shape, migration and proliferation. Previously we showed that ARHGAP18 in endothelial cells is important in cell junctions. Here we show, using structured illumination microscopy (SIM), ground-state depletion (GSD), and total internal reflection fluorescence microscopy (TIRF) that a proportion of ARHGAP18 localizes to microtubules in endothelial cells, as well as in nonendothelial cells, an association confirmed biochemically. In endothelial cells, some ARHGAP18 puncta also colocalized to Weibel-Palade bodies on the microtubules. Depletion of ARHGAP18 by small interfering RNA or analysis of endothelial cells isolated from ARHGAP18-knockout mice showed microtubule destabilization, as evidenced by altered morpholo2017-01-01T00:00:00Z2017 Apr2025-04-04T12:39:07.969Z2019-03-27T02:41:18ZS-EPMC53911832825192510.1091/mbc.E16-05-0285