Regulation of PTEN/Akt and MAP kinase signaling pathways by the ubiquitin ligase activators Ndfip1 and Ndfip2

Mund, Thomas; Pelham, Hugh R.B.

doi:10.1073/pnas.0911714107

Cited by 65 publications

(46 citation statements)

References 35 publications

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“…Cells were transfected twice, 72 and 48 hours before the experiment. The siRNA used as a control was a scrambled siRNA, 5¢-GAUUGGAUCUCCCUACUAU-3¢ (Mund and Pelham, 2010). …”

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confidence: 99%

Pacsin 2 is recruited to caveolae and functions in caveolar biogenesis

Hansen

Howard

Nichols

2011

Journal of Cell Science

148

159

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SummaryThe pacsin (also termed syndapin) protein family is well characterised structurally. They contain F-BAR domains associated with the generation or maintenance of membrane curvature. The cell biology of these proteins remains less understood. Here, we initially confirm that EHD2, a protein previously shown biochemically to be present in caveolar fractions and to bind to pacsins, is a caveolar protein. We go on to report that GFP-pacsin 2 can be recruited to caveolae, and that endogenous pacsin 2 partially colocalises with caveolin 1 at the plasma membrane. Analysis of the role of pacsin 2 in caveolar biogenesis using small interfering RNA (siRNA) reveals that loss of pacsin 2 function results in loss of morphologically defined caveolae and accumulation of caveolin proteins within the plasma membrane. Overexpression of the F-BAR domain of pacsin 2 (but not the related F-BAR domains of CIP4 and FBP17) disrupts caveolar morphogenesis or trafficking, implying that pacsin 2 interacts with components required for these processes. We propose that pacsin 2 has an important role in the formation of plasma membrane caveolae. Journal of Cell Sciencesix-helix bundle. The concave surface of this a-helical coiled-coil region is markedly enriched in positively charged residues, conferring membrane affinity (Edeling et al., 2009;Rao et al., 2010;Shimada et al., 2009;Wang et al., 2009). The propensity of the F-BAR domain in pacsins to bend membranes is regulated by autoinhibition, as the SH3 domain can act as an intramolecular clamp (Edeling et al., 2009;Rao et al., 2010;Shimada et al., 2009;Wang et al., 2009). This clamp is released when the SH3 domain binds to the proline-rich region of dynamin, thereby potentially coupling the membrane-bending function of pacsins to dynamin activity (Kessels et al., 2006;Rao et al., 2010). The SH3 domain might also interact with N-WASP and therefore link pacsin function to the nucleation of F-actin (Kessels and Qualmann, 2002;Kessels and Qualmann, 2004). Pacsins have been implicated in a variety of cellular roles, including endocytosis (Anggono et al., 2006;Kessels and Qualmann, 2002;Modregger et al., 2000), notochord development (Edeling et al., 2009), neuromorphogenesis (Dharmalingam et al., 2009) and gastrulation (Cousin et al., 2008).The data outlined above make EHD2 a good candidate to be a caveolar protein and raise the possibility that pacsin 2 might also be associated with caveolae. Here, we set out to test these hypotheses and to characterise the potential function of pacsin 2 in caveolar biogenesis. Results EHD2 and Pacsin 2 can be recruited to caveolaeIn order to confirm that EHD2 can be recruited to caveolae, we expressed GFP-EHD2 in HeLa cells and labelled caveolin 1 using indirect immunofluorescence (supplementary material Fig. S1a). GFP-EHD2 was distributed in membrane puncta and in long tubes (Blume et al., 2007; Daumke et al., 2007). The membrane puncta colocalised with caveolin 1, with over 75% of GFP-EHD2 puncta also containing caveolin 1 (supplementary material Fig. ...

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“…Cells were transfected twice, 72 and 48 hours before the experiment. The siRNA used as a control was a scrambled siRNA, 5¢-GAUUGGAUCUCCCUACUAU-3¢ (Mund and Pelham, 2010). …”

mentioning

confidence: 99%

Pacsin 2 is recruited to caveolae and functions in caveolar biogenesis

Hansen

Howard

Nichols

2011

Journal of Cell Science

148

159

View full text Add to dashboard Cite

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“…Researches have shown that Ndfip1 interacts with several Nedd4 E3 ligase family members and acts as recruiter and activator of Nedd4 family E3-mediated protein ubiquitination and degradation (13)(14)(15). In this study, we demonstrate that Ndfip1 accelerates HECT domain-containing Nedd4 family member Smurf1-mediated MAVS degradation by enhancing interaction between Smurf1 and MAVS.…”

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confidence: 53%

Ndfip1 Negatively Regulates RIG-I–Dependent Immune Signaling by Enhancing E3 Ligase Smurf1-Mediated MAVS Degradation

Wang

Tong

2012

The Journal of Immunology

103

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Ndfip1 functions as both a recruiter and an activator of multiple HECT domain E3 ubiquitin ligases of the Nedd4 family. In this study, we demonstrate that Ndfip1 is involved in the ubiquitin-mediated degradation of mitochondrial antiviral signaling (MAVS), which is a key adaptor protein in RIG-I–like receptor–mediated immune signaling. We found that overexpression of Ndfip1 severely impaired MAVS and Sendai virus–mediated activation of IFN-stimulated response element, NF-κB, IFN-β promoter, and polyinosinic-polycytidylic acid or influenza virus RNA–stimulated IRF-3 phosphorylation, as well as the transcription of IFN-β. This functional interaction was confirmed by knockdown of Ndfip1, which facilitated MAVS-mediated downstream signaling and elevated MAVS protein levels. Further analysis indicated that Ndfip1 enhances both self-ubiquitination of HECT domain-containing E3 ubiquitin ligase Smurf1 and its interaction with MAVS, and eventually promotes MAVS degradation. In addition, the activation of IFN-β by MAVS, influenza virus RNA, polyinosinic-polycytidylic acid, and Sendai virus was enhanced in Ndfip1 knockdown cells. These results reveal that Ndfip1 is a potent inhibitor of MAVS-mediated antiviral response.

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“…Indeed mammalian Ndfips have recently been shown to regulate members of the EGF pathway by promoting Nedd4 family E3-mediated ubiquitination of several pathway members, including PTEN, c-Cbl and Src family kinases. 31 Further studies await availability of specific dNdfip mutants, as all currently available transposon insertion lines also affect Keren, a gene that overlaps with dNdfip, sharing a common 5 0 -UTR and thus, complicating the analysis of the specific contribution of dNdfip to the phenotype.…”

Section: Discussionmentioning

confidence: 99%