Ras-Association Domain of Sorting Nexin 27 Is Critical for Regulating Expression of GIRK Potassium Channels

Balana, Bartosz; Bahima, Laia; Bodhinathan, Karthik; Taura, Jaume; Taylor, Natalie M.; Nettleton, Margaret; Ciruela, Francisco; Slesinger, Paul A.

doi:10.1371/journal.pone.0059800

Cited by 21 publications

(20 citation statements)

References 31 publications

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“…This phenomenon has been observed in Rap1-interacting adaptor molecule (RIAM), which contains both Rasassociation and PH domains and requires both Rap1 GTPase interaction, mediated by the Ras-association domain, and PtdInsP binding, mediated by the PH domain, for cell surface recruitment in activated T-cells (Wynne et al, 2012). The previous findings showing that SNX27 can associate with a small GTPase through its Ras-association-domain-related F1 module (Balana et al, 2013;Ghai et al, 2013;Loo et al, 2014), and the discovery here that it can bind PtdInsP species through the F3 module present a tempting parallel to the RIAM system, and suggests that PtdInsP, cargo and GTPase interactions may co-operatively contribute to membrane localization of SNX27 following certain cell stimuli.…”

Section: Discussionmentioning

confidence: 82%

“…In fact the b2 integrin subunit of LFA-1 has been shown to bind SNX27 in vitro in peptide arrays (Ghai et al, 2013). Furthermore, the interaction of SNX27 with cytoplasmic signaling molecules, including small GTPases (Balana et al, 2013;, diacylglycerol kinase f (DGKf) (Rincón et al, 2011;Rincón et al, 2007), and cytohesinassociated scaffolding protein (CASP) , suggests that it has an additional or related role in the scaffolding of signaling complexes.…”

Section: Discussionmentioning

confidence: 99%

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Phosphoinositide binding by the SNX27 FERM domain regulates localisation at the immune synapse of activated T-cells

Ghai

Tello-Lafoz

Norwood

et al. 2014

Journal of Cell Science

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Sorting nexin 27 (SNX27) controls the endosomal-to-cell-surface recycling of diverse transmembrane protein cargos. Crucial to this function is the recruitment of SNX27 to endosomes which is mediated by the binding of phosphatidylinositol-3-phosphate (PtdIns3P) by its phox homology (PX) domain. In T-cells, SNX27 localizes to the immunological synapse in an activation-dependent manner, but the molecular mechanisms underlying SNX27 translocation remain to be clarified. Here, we examined the phosphoinositide-lipid-binding capabilities of full-length SNX27, and discovered a new PtdInsPbinding site within the C-terminal 4.1, ezrin, radixin, moesin (FERM) domain. This binding site showed a clear preference for bi-and tri-phosphorylated phophoinositides, and the interaction was confirmed through biophysical, mutagenesis and modeling approaches. At the immunological synapse of activated T-cells, cell signaling regulates phosphoinositide dynamics, and we find that perturbing phosphoinositide binding by the SNX27 FERM domain alters the SNX27 distribution in both endosomal recycling compartments and PtdIns(3,4,5)P 3 -enriched domains of the plasma membrane during synapse formation. Our results suggest that SNX27 undergoes dynamic partitioning between different membrane domains during immunological synapse assembly, and underscore the contribution of unique lipid interactions for SNX27 orchestration of cargo trafficking.

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Phosphoinositide binding by the SNX27 FERM domain regulates localisation at the immune synapse of activated T-cells

Ghai

Tello-Lafoz

Norwood

et al. 2014

Journal of Cell Science

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“…The recombinant extension in the N terminus, either His-tags (49), large fluorescent proteins (20,50,51), or small oligopeptide tags for antibody staining (52), are generally considered to have little impact on biological functions (53)(54)(55). We find that a hexahistine tag on the N terminus of 6His-Ras(C181) slightly shifts the measured dimer K d (to 344 ± 28 molecules/μm 2 ) without changing the qualitative behavior of H-Ras dimerization (Fig.…”

Section: The Equilibrium Dissociation Constant For H-ras Dimerization Onmentioning

confidence: 82%

H-Ras forms dimers on membrane surfaces via a protein–protein interface

Lin

Iversen

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

150

165

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The lipid-anchored small GTPase Ras is an important signaling node in mammalian cells. A number of observations suggest that Ras is laterally organized within the cell membrane, and this may play a regulatory role in its activation. Lipid anchors composed of palmitoyl and farnesyl moieties in H-, N-, and K-Ras are widely suspected to be responsible for guiding protein organization in membranes. Here, we report that H-Ras forms a dimer on membrane surfaces through a protein-protein binding interface. A Y64A point mutation in the switch II region, known to prevent Son of sevenless and PI3K effector interactions, abolishes dimer formation. This suggests that the switch II region, near the nucleotide binding cleft, is either part of, or allosterically coupled to, the dimer interface. By tethering H-Ras to bilayers via a membrane-miscible lipid tail, we show that dimer formation is mediated by protein interactions and does not require lipid anchor clustering. We quantitatively characterize H-Ras dimerization in supported membranes using a combination of fluorescence correlation spectroscopy, photon counting histogram analysis, time-resolved fluorescence anisotropy, single-molecule tracking, and step photobleaching analysis. The 2D dimerization K d is measured to be ∼1 × 10 3 molecules/μm 2 , and no higher-order oligomers were observed. Dimerization only occurs on the membrane surface; H-Ras is strictly monomeric at comparable densities in solution. Analysis of a number of H-Ras constructs, including key changes to the lipidation pattern of the hypervariable region, suggest that dimerization is a general property of native H-Ras on membrane surfaces.Ras signaling | Ras assay

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“…A more detailed analysis of β2-adrenergic receptor recycling revealed that sorting nexin 27 (SNX27) links β2-adrenergic receptors to the retromer tubule, which is important for recycling back to the plasma membrane (Temkin et al, 2011). In addition to the PDZ domain and PX domain, SNX27 contains a RA / FERM domain that is proposed to bind Ras-like GTPase proteins (Balana et al, 2013; Ghai et al, 2011); perhaps the RA domain recruits additional binding partners to regulate interaction with the retromer complex and trafficking from the early endosome. Using a proteomics approach, Steinberg et al (2013) discovered over 100 cell surface proteins that required a SNX27–retromer to prevent lysosomal degradation and maintain surface levels.…”

Section: Discussionmentioning

confidence: 99%

Sorting Nexin 27 Regulation of G Protein-Gated Inwardly Rectifying K+ Channels Attenuates In Vivo Cocaine Response

Munoz

Slesinger

2014

Neuron

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The subcellular pathways that regulate G protein-gated inwardly rectifying potassium (GIRK or Kir3) channels are important for controlling the excitability of neurons. Sorting nexin 27 (SNX27) is a PDZ-containing protein known to bind GIRK2c/3 channels but its function in vivo is poorly understood. Here, we investigated the role of SNX27 in regulating GIRK currents in dopamine (DA) neurons of the ventral tegmental area (VTA). Mice lacking SNX27 in DA neurons exhibited reduced GABABR-activated GIRK currents but had normal Ih currents and dopamine D2R-activated GIRK currents. Expression of GIRK2a, a SNX27-insensitive splice-variant, restored GABABR-activated GIRK currents in SNX27-deficient DA neurons. Remarkably, mice with significantly reduced GABABR-activated GIRK currents in only DA neurons were hypersensitive to cocaine, and could be restored to a normal locomotor response with GIRK2a expression. These results identify a novel pathway for regulating excitability of VTA DA neurons, highlighting SNX27 as a promising target for treating addiction.

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Ras-Association Domain of Sorting Nexin 27 Is Critical for Regulating Expression of GIRK Potassium Channels

Cited by 21 publications

References 31 publications

Phosphoinositide binding by the SNX27 FERM domain regulates localisation at the immune synapse of activated T-cells

Phosphoinositide binding by the SNX27 FERM domain regulates localisation at the immune synapse of activated T-cells

H-Ras forms dimers on membrane surfaces via a protein–protein interface

Sorting Nexin 27 Regulation of G Protein-Gated Inwardly Rectifying K+ Channels Attenuates In Vivo Cocaine Response

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