K33-Linked Polyubiquitination of Coronin 7 by Cul3-KLHL20 Ubiquitin E3 Ligase Regulates Protein Trafficking

• Published in: Molecular cell 2014-05, Vol.54 (4), p.586-600
• Main Authors: Yuan, Wei-Chien, Lee, Yu-Ru, Lin, Shu-Yu, Chang, Li-Ying, Tan, Yen Pei, Hung, Chin-Chun, Kuo, Jean-Cheng, Liu, Cheng-Hsin, Lin, Mei-Yao, Xu, Ming, Chen, Zhijian J., Chen, Ruey-Hwa
• Format: Article
• Language: English
• Subjects: Actins - genetics; Actins - metabolism; Adaptor Proteins, Vesicular Transport - genetics; Adaptor Proteins, Vesicular Transport - metabolism; Animals; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell Line; Cercopithecus aethiops; COS Cells; Cullin Proteins - genetics; Cullin Proteins - metabolism; Golgi Apparatus - metabolism; HEK293 Cells; HeLa Cells; Humans; Lysine - metabolism; Microfilament Proteins - genetics; Microfilament Proteins - metabolism; Protein Transport; trans-Golgi Network - metabolism; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism; Ubiquitination
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/j.molcel.2014.03.035

Ubiquitin chains are formed as structurally distinct polymers via different linkages, and several chain types including K33-linkage remain uncharacterized. Here, we describe a role for K33-polyubiquitination in protein trafficking. We show that the Cullin 3 (Cul3) substrate adaptor KLHL20 is localized to the trans-Golgi network (TGN) and is important for post-Golgi trafficking by promoting the biogenesis of TGN-derived transport carriers. The Cul3-KLHL20 ubiquitin E3 ligase catalyzes a nondegradable, K33-linked polyubiquitination on coronin 7 (Crn7), which facilitates Crn7 targeting to TGN through a ubiquitin-dependent interaction with Eps15. Blockage of K33-chain formation, Crn7 ubiquitination, or disruption of Crn7-Eps15 interaction impairs TGN-pool F-actin assembly, a process essential for generating transport carriers. Enforced targeting of Crn7 to TGN bypasses the requirement of K33-ubiquitination for TGN-pool F-actin assembly and post-Golgi trafficking. Our study reveals a role of KLHL20-mediated K33-ubiquitination of Crn7 in post-Golgi transport and identifies a cellular recognition mechanism for this ubiquitin chain type. [Display omitted] •Cul3-KLHL20 E3 ligase promotes post-Golgi transport to plasma membrane and endosomes•The trafficking effects of KLHL20 are mediated by K33-polyubiquitination of Crn7•K33-polyubiquitination targets Crn7 to TGN by interacting with Eps15 UIMs•Crn7 TGN recruitment facilitates F-actin assembly and transport carrier biogenesis Ubiquitin chains are formed as structurally distinct polymers via different linkages. Yuan et al. report that K33-linked ubiquitination connects an actin-regulatory protein coronin 7 to Golgi-localized ubiquitin-binding protein Eps15. This connection enables actin assembly at Golgi to promote protein trafficking, thus identifying a function of this atypical ubiquitin chain.