Cdc42 Regulates Microtubule‐Dependent Golgi Positioning |
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Authors: | Heidi Hehnly Weidong Xu Ji‐Long Chen Mark Stamnes |
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Institution: | 1. Department of Molecular Physiology & Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA;2. Current address: Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA;3. Current address: Department of Pediatrics, Research Institute of Evanston Hospital, Evanston, IL 60201, USA;4. Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA;5. Current address: Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China |
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Abstract: | The molecular mechanisms underlying cytoskeleton‐dependent Golgi positioning are poorly understood. In mammalian cells, the Golgi apparatus is localized near the juxtanuclear centrosome via dynein‐mediated motility along microtubules. Previous studies implicate Cdc42 in regulating dynein‐dependent motility. Here we show that reduced expression of the Cdc42‐specific GTPase‐activating protein, ARHGAP21, inhibits the ability of dispersed Golgi membranes to reposition at the centrosome following nocodazole treatment and washout. Cdc42 regulation of Golgi positioning appears to involve ARF1 and a binding interaction with the vesicle‐coat protein coatomer. We tested whether Cdc42 directly affects motility, as opposed to the formation of a trafficking intermediate, using a Golgi capture and motility assay in permeabilized cells. Disrupting Cdc42 activation or the coatomer/Cdc42 binding interaction stimulated Golgi motility. The coatomer/Cdc42‐sensitive motility was blocked by the addition of an inhibitory dynein antibody. Together, our results reveal that dynein and microtubule‐dependent Golgi positioning is regulated by ARF1‐, coatomer‐, and ARHGAP21‐dependent Cdc42 signaling. |
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Keywords: | ARF1 ARHGAP21 Cdc42 coatomer dynein Golgi apparatus microtubule |
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