Mattingly, Brendan ChristopherBuechner, Matthew2017-03-062017-03-062012-11-01Mattingly, Brendan C., and Matthew Buechner. "The FGD Homologue EXC-5 Regulates Apical Trafficking in C. Elegans Tubules." Developmental Biology 359.1 (2011): 59-72.https://hdl.handle.net/1808/23345Maintenance of the shape of biological tubules is critical for development and physiology of metazoan organisms. Loss of function of the C. elegans FGD protein EXC-5 allows large fluid-filled cysts to form in the lumen of the single-cell excretory canal tubules, while overexpression of exc-5 causes defects at the tubule’s basolateral surface. We have examined the effects of altering expression levels of exc-5 on the distribution of fluorescently-marked subcellular organelles. In exc-5 mutants, early endosomes build up in the cell, especially in areas close to cysts, while recycling endosomes are depleted. Endosome morphology changes prior to cyst formation. Conversely, when exc-5 is overexpressed, recycling endosomes are enriched. Since FGD proteins activate the small GTPases CDC42 and Rac, these results support the hypothesis that EXC-5 acts through small GTPases to move material from apical early endosomes to recycling endosomes, and that loss of such movement is likely the cause of tubule deformation both in nematodes and in tissues affected by FGD dysfunction such as Charcot-Marie-Tooth Syndrome type 4H.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License 3.0 (CC BY-NC-ND 3.0 US), which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.http://creativecommons.org/licenses/by-nc-nd/3.0/Charcot-Marie-Tooth SyndromeFGDEEA1RME-1RabCDC42Endosome recyclingArticle10.1016/j.ydbio.2011.08.011https://orcid.org/0000-0002-2103-9399openAccess