Rabankyrin-5 Interacts with EHD1 and Vps26 to Regulate Endocytic Trafficking and Retromer Function

Department of Biochemistry and Molecular Biology and Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA.
Traffic (Impact Factor: 4.35). 01/2012; 13(5):745-57. DOI: 10.1111/j.1600-0854.2012.01334.x
Source: PubMed


Rabankyrin-5 (Rank-5) has been implicated as an effector of the small GTPase Rab5 and plays an important role in macropinocytosis. We have now identified Rank-5 as an interaction partner for the recycling regulatory protein, Eps15 homology domain 1 (EHD1). We have demonstrated this interaction by glutathione S-transferase-pulldown, yeast two-hybrid assay, isothermal calorimetry and co-immunoprecipitation, and found that the binding occurs between the EH domain of EHD1 and the NPFED motif of Rank-5. Similar to EHD1, we found that Rank-5 colocalizes and interacts with components of the retromer complex such as vacuolar protein sorting 26 (Vps26), suggesting a role for Rank-5 in retromer-based transport. Indeed, depletion of Rank-5 causes mislocalization of Vps26 and affects both the retrieval of mannose 6-phosphate receptor transport to the Golgi from endosomes and biosynthetic transport. Moreover, Rank-5 is required for normal retromer distribution, as overexpression of a wild-type Rank-5-small interfering RNA-resistant construct rescues retromer mislocalization. Finally, we show that depletion of either Rank-5 or EHD1 impairs secretion of vesicular stomatitis virus glycoprotein. Overall, our data identify a new interaction between Rank-5 and EHD1, and novel endocytic regulatory roles that include retromer-based transport and secretion.

Download full-text


Available from: Calliste Reiling, Jul 10, 2014
  • Source
    • "The SNX dimer, currently understood to comprise a combination of SNX1 or SNX2 with SNX5 or SNX6 (Wassmer et al., 2007), binds to phosphoinositol 3-phosphate through its phox homology domains and induces membrane curvature by the action of its C-terminal BAR (Bin- Amphiphysin-Rvs) domains (Kurten et al., 2001; Cheever et al., 2001; Yu and Lemmon, 2001; Cozier et al., 2002; Carlton et al., 2004). The tubules generated by the SNX dimer are stabilised by EHD1 (also known as RME-1), which associates with the CSC (Gokool et al., 2007b; Zhang et al., 2012). Although SNX5 and SNX6 do not drive membrane tubulation (van Weering et al., 2012), both interact with the p150Glued component of dynactin (Wassmer et al., 2009; Hong et al., 2009) and, therefore, link retromer-mediated protein sorting with microtubules through dynein. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Retromer is a vital element of the endosomal protein sorting machinery, and comprises two sub-complexes that operate together to sort membrane proteins (cargo) and tubulate membranes. Tubules are formed by the sorting nexin dimer, a key component of which is SNX1. Cargo selection is mediated by the VPS35-VPS29-VPS26 trimer, which additionally recruits the WASH complex via VPS35 binding to the WASH complex subunit FAM21. Loss of WASH complex function leads to dysregulation of endosome tubulation, although it is not clear how this occurs. Here we show that FAM21 also binds to the SNX1-interacting DNAJ protein RME-8. Loss of RME-8 causes altered kinetics of SNX1 membrane association and a pronounced increase in highly branched endosomal tubules. Extending the observations of Popoff et al. (2009), we show that these contain membrane proteins dependent on WASH complex activity for localization to the plasma membrane. We therefore propose that the RME-8/WASH complex interaction provides a potential means to coordinate the activity of the WASH complex with the membrane-tubulating function of the sorting nexins at sites where retromer-mediated endosomal protein sorting occurs.
    Full-text · Article · Mar 2014 · Journal of Cell Science
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Retrograde trafficking mediates the transport of endocytic membranes from endosomes to the trans-Golgi network (TGN). Dysregulation of these pathways can result in multiple ailments, including late-onset Alzheimer disease. One of the key retrograde transport regulators, the retromer complex, is tightly controlled by many factors, including the C-terminal Eps15 homology domain (EHD) proteins. This mini-review focuses on recent findings and discusses the regulation of the retromer complex by EHD proteins and the novel EHD1 interaction partner, Rabankyrin-5 (Rank-5).
    Full-text · Article · Jul 2012
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The retromer complex is a vital element of the endosomal protein sorting machinery that is conserved across all eukaryotes. Retromer is most closely associated with the endosome-to-Golgi retrieval pathway and is necessary to maintain an active pool of hydrolase receptors in the trans-Golgi network. Recent progress in studies of retromer have identified new retromer-interacting proteins, including the WASH complex and cargo such as the Wntless/MIG-14 protein, which now extends the role of retromer beyond the endosome-to-Golgi pathway and has revealed that retromer is required for aspects of endosome-to-plasma membrane sorting and regulation of signalling events. The interactions between the retromer complex and other macromolecular protein complexes now show how endosomal protein sorting is coordinated with actin assembly and movement along microtubules, and place retromer squarely at the centre of a complex set of protein machinery that governs endosomal protein sorting. Dysregulation of retromer-mediated endosomal protein sorting leads to various pathologies, including neurodegenerative diseases such as Alzheimer disease and spastic paraplegia and the mechanisms underlying these pathologies are starting to be understood. In this Commentary, I will highlight recent advances in the understanding of retromer-mediated endosomal protein sorting and discuss how retromer contributes to a diverse set of physiological processes.
    Full-text · Article · Nov 2012 · Journal of Cell Science
Show more