Regulation of WASH-dependent actin polymerization and protein trafficking by ubiquitination

  • Cell. 2013 Feb 28;152(5):1051-64. doi: 10.1016/j.cell.2013.01.051.
Yi-Heng Hao  1 ,  Jennifer M Doyle ,  Saumya Ramanathan ,  Timothy S Gomez ,  Da Jia ,  Ming Xu ,  Zhijian J Chen ,  Daniel D Billadeau ,  Michael K Rosen ,  Patrick Ryan Potts
Affiliations
  • 1. Department of Physiology, UT Southwestern Dallas, TX 75390, USA.
PMID: 23452853 DOI: 10.1016/j.cell.2013.01.051
Abstract

Endosomal protein trafficking is an essential cellular process that is deregulated in several diseases and targeted by pathogens. Here, we describe a role for ubiquitination in this process. We find that the E3 RING ubiquitin Ligase, MAGE-L2-TRIM27, localizes to endosomes through interactions with the retromer complex. Knockdown of MAGE-L2-TRIM27 or the Ube2O E2 ubiquitin-conjugating enzyme significantly impaired retromer-mediated transport. We further demonstrate that MAGE-L2-TRIM27 ubiquitin Ligase activity is required for nucleation of endosomal F-actin by the WASH regulatory complex, a known regulator of retromer-mediated transport. Mechanistic studies showed that MAGE-L2-TRIM27 facilitates K63-linked ubiquitination of WASH K220. Significantly, disruption of WASH ubiquitination impaired endosomal F-actin nucleation and retromer-dependent transport. These findings provide a cellular and molecular function for MAGE-L2-TRIM27 in retrograde transport, including an unappreciated role of K63-linked ubiquitination and identification of an activating signal of the WASH regulatory complex.