The Connecdenn DENN domain: a GEF for Rab35 mediating cargo-specific exit from early endosomes. Mol Cell

Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada.
Molecular cell (Impact Factor: 14.02). 02/2010; 37(3):370-82. DOI: 10.1016/j.molcel.2009.12.037
Source: PubMed


The DENN domain is an evolutionarily ancient protein module. Mutations in the DENN domain cause developmental defects in plants and human diseases, yet the function of this common module is unknown. We now demonstrate that the connecdenn/DENND1A DENN domain functions as a guanine nucleotide exchange factor (GEF) for Rab35 to regulate endosomal membrane trafficking. Loss of Rab35 activity causes an enlargement of early endosomes and inhibits MHC class I recycling. Moreover, it prevents early endosomal recruitment of EHD1, a common component of tubules involved in endosomal cargo recycling. Our data reveal an enzymatic activity for a DENN domain and demonstrate that distinct Rab GTPases can recruit a common protein machinery to various sites within the endosomal network to establish cargo-selective recycling pathways.

  • Source
    • "DENN domain proteins have been shown to function as RAB GEFs (GDP-GTP exchange factors) as well as interact with non-RAB proteins (Allaire et al., 2010; Yoshimura et al., 2010; reviewed in Marat et al., 2011). The DENND2 subfamily consists of four members, A through D. While all four DENND2 subfamily members could behave as RAB9 GEFs by in vitro GDP release activity, the in vivo functions for DENND2B, DENND2C, and DENND2D are unknown, as only DENND2A knockdown phenocopies the lysosomal defect caused by RAB9 inactivation in HeLa cells (Yoshimura et al., 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The mechanisms regulating human embryonic stem (ES) cell self-renewal and differentiation are not well defined in part due to the lack of tools for forward genetic analysis. We present a piggyBac transposon gain of function screen in human ES cells that identifies DENND2C, which genetically cooperates with NANOG to maintain self-renewal in the presence of retinoic acid. We show that DENND2C negatively regulates RHOA activity, which cooperates with NANOG to block differentiation. It has been recently shown that RHOA exists in the nucleus and is activated by DNA damage; however, its nuclear function remains unknown. We discovered that RHOA associates with DNA and that DENND2C affects nuclear RHOA localization, activity, and DNA association. Our study illustrates the power of piggyBac as a cost-effective, efficient, and easy to use tool for forward genetic screens in human ES cells and provides insight into the role of RHOA in the nucleus. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Full-text · Article · Apr 2015 · Stem Cell Reports
  • Source
    • "A recent GWAS conducted in Han Chinese women identified single nucleotide polymorphisms (SNPs) at LHCGR, THADA, and DENND1A genes to be strongly associated with PCOS (Chen et al., 2011; Cui et al., 2013). DENND1A encodes the protein DENN/MADD, a member of the connecdenn family which functions as a component of clathrinmediated endocytosis machinery (Marat and McPherson, 2010), and Rab35 activated endocytotic trafficking, whereby it controls recycling of endosomal cargo (Marat and McPherson, 2010; Allaire et al., 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Recent genome-wide association studies and replication analyses reported an association between variants of DENND1A gene and polycystic ovary syndrome (PCOS), mostly in Asians. We therefore examined whether the common DENND1A SNPs rs10818854, rs2479106, and rs10986105 are associated with PCOS in Bahraini Arab population. This case-control study involved 191 women with PCOS diagnosed according to the Rotterdam criteria, and 202 control women. SNP genotyping was performed by the allelic discrimination in real-time PCR. The outcome was that the minor allele frequencies of SNPs rs10818854, rs2479106, and rs10986105 were similar between women with PCOS and control women (P>0.05), even before correcting for multiple testing, and none of the tested DENND1A SNPs were associated with PCOS under co-dominant, dominant, or recessive genetic models. None of the tested DENND1A variants were associated with PCOS features (hirsutism, insulin sensitivity, menses pattern, free testosterone, and free androgen index). Taking common GTA haplotype as reference (OR=1.00), [rs10818854/rs2479106/rs10986105] 3-locus haplotype analysis demonstrated lack of association of any of the DENND1A haplotypes with PCOS, even before correcting for multiple testing. To conclude we demonstrated lack of association of DENND1A SNPs rs10818854, rs2479106, and rs10986105, previously associated with PCOS in Asians, with PCOS in Bahraini Arab women. Copyright © 2015 Elsevier B.V. All rights reserved.
    Full-text · Article · Jan 2015 · Gene
  • Source
    • "Rab35 is recruited to coated pits by connecdenn, a scaffolding protein that shares interactions with the adaptor complex AP-2 and src-homology 3 domain containing endocytosis proteins (Allaire and others 2006). Connecdenn is also a GTP exchange factor (GEF) for Rab35 and therefore facilitates its function (Allaire and others 2010). As stated above, the slow cargo recycling route involves traffic from the ERC back to the plasma membrane . "
    [Show abstract] [Hide abstract]
    ABSTRACT: Synaptic vesicle (SV) retrieval from the presynaptic plasma membrane occurs via a variety of different and complementary modes. The dominant retrieval mode during high-intensity stimulation is activity-dependent bulk endocytosis (ADBE). ADBE involves the generation of endosomes direct from the plasma membrane which then donate membrane and cargo to form SVs that replenish the reserve SV pool. Recent evidence has suggested that ADBE may involve an additional endosomal processing step to produce a mature, functional SV. This suggests that ADBE may utilize key molecules or indeed whole pathways from classical endocytic recycling routes that are ubiquitous across all cell types. This review will assess the current evidence for a contribution of endocytic recycling to the SV life cycle, with a particular focus on ADBE. In doing so it highlights points where both routes may either converge or exploit existing mechanisms to ensure efficient generation of SVs during high-intensity stimulation.
    Full-text · Article · Jul 2014 · The Neuroscientist
Show more