Activity-Regulated Cytoskeleton-Associated Protein Controls AMPAR Endocytosis through a Direct Interaction with Clathrin-Adaptor Protein 2

HIV-1 Nef-mediated CD4 downmodulation involves various host factors. We investigated the importance of AP-1, AP-2, AP-3, V1H-ATPase, β-COP, and ACOT8 for CD4 downmodulation in HIV-1-infected short hairpin RNA (shRNA)-expressing CD4+T cells and characterized direct interaction with Nef by Förster resonance energy transfer (FRET). Binding of lentiviral Nefs to CD4 and AP-2 was conserved, and only AP-2 knockdown impaired Nef-mediated CD4 downmodulation from primary T cells. Altogether, among the factors tested, AP-2 is the most important player for Nef-mediated CD4 downmodulation.

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Type Iγ phosphatidylinositol phosphate kinase modulates adherens junction and E-cadherin trafficking via a direct interaction with μ1B adaptin

The Journal of Cell Biology ◽

10.1083/jcb.200606023 ◽

2007 ◽

Vol 176 (3) ◽

pp. 343-353 ◽

Cited By ~ 109

Author(s):

Kun Ling ◽

Shawn F. Bairstow ◽

Chateen Carbonara ◽

Dmitry A. Turbin ◽

David G. Huntsman ◽

...

Keyword(s):

Germline Mutation ◽

Basolateral Membrane ◽

Adherens Junction ◽

Adaptor Protein ◽

Direct Interaction ◽

Phosphatidylinositol Phosphate ◽

Polarized Epithelia ◽

Clathrin Adaptor ◽

E Cadherin ◽

Phosphatidylinositol Phosphate Kinase

Assembly of E-cadherin–based adherens junctions (AJ) is obligatory for establishment of polarized epithelia and plays a key role in repressing the invasiveness of many carcinomas. Here we show that type Iγ phosphatidylinositol phosphate kinase (PIPKIγ) directly binds to E-cadherin and modulates E-cadherin trafficking. PIPKIγ also interacts with the μ subunits of clathrin adaptor protein (AP) complexes and acts as a signalling scaffold that links AP complexes to E-cadherin. Depletion of PIPKIγ or disruption of PIPKIγ binding to either E-cadherin or AP complexes results in defects in E-cadherin transport and blocks AJ assembly. An E-cadherin germline mutation that loses PIPKIγ binding and shows disrupted basolateral membrane targeting no longer forms AJs and leads to hereditary gastric cancers. These combined results reveal a novel mechanism where PIPKIγ serves as both a scaffold, which links E-cadherin to AP complexes and the trafficking machinery, and a regulator of trafficking events via the spatial generation of phosphatidylinositol-4,5-bisphosphate.

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The AP2 clathrin adaptor protein complex regulates the abundance of GLR-1 glutamate receptors in the ventral nerve cord of Caenorhabditis elegans

Molecular Biology of the Cell ◽

10.1091/mbc.e14-06-1048 ◽

2015 ◽

Vol 26 (10) ◽

pp. 1887-1900 ◽

Cited By ~ 5

Author(s):

Steven D. Garafalo ◽

Eric S. Luth ◽

Benjamin J. Moss ◽

Michael I. Monteiro ◽

Emily Malkin ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Nerve Cord ◽

Ventral Nerve Cord ◽

Secretory Pathway ◽

Adaptor Protein ◽

Intracellular Compartments ◽

Clathrin Adaptor ◽

Strength And Plasticity

Regulation of glutamate receptor (GluR) abundance at synapses by clathrin-mediated endocytosis can control synaptic strength and plasticity. We take advantage of viable, null mutations in subunits of the clathrin adaptor protein 2 (AP2) complex in Caenorhabditis elegans to characterize the in vivo role of AP2 in GluR trafficking. In contrast to our predictions for an endocytic adaptor, we found that levels of the GluR GLR-1 are decreased at synapses in the ventral nerve cord (VNC) of animals with mutations in the AP2 subunits APM-2/μ2, APA-2/α, or APS-2/σ2. Rescue experiments indicate that APM-2/μ2 functions in glr-1–expressing interneurons and the mature nervous system to promote GLR-1 levels in the VNC. Genetic analyses suggest that APM-2/μ2 acts upstream of GLR-1 endocytosis in the VNC. Consistent with this, GLR-1 accumulates in cell bodies of apm-2 mutants. However, GLR-1 does not appear to accumulate at the plasma membrane of the cell body as expected, but instead accumulates in intracellular compartments including Syntaxin-13– and RAB-14–labeled endosomes. This study reveals a novel role for the AP2 clathrin adaptor in promoting the abundance of GluRs at synapses in vivo, and implicates AP2 in the regulation of GluR trafficking at an early step in the secretory pathway.

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Phosphoserine acidic cluster motifs bind distinct basic regions on the μ subunits of clathrin adaptor protein complexes

Journal of Biological Chemistry ◽

10.1074/jbc.ra118.003080 ◽

2018 ◽

Vol 293 (40) ◽

pp. 15678-15690 ◽

Cited By ~ 4

Author(s):

Rajendra Singh ◽

Charlotte Stoneham ◽

Christopher Lim ◽

Xiaofei Jia ◽

Javier Guenaga ◽

...

Keyword(s):

Protein Complexes ◽

Adaptor Protein ◽

Clathrin Adaptor

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PACS-1 and Adaptor Protein-1 Mediate ACTH Trafficking to the Regulated Secretory Pathway

10.1101/446229 ◽

2018 ◽

Author(s):

Brennan S. Dirk ◽

Christopher End ◽

Emily N. Pawlak ◽

Logan R. Van Nynatten ◽

Rajesh Abraham Jacob ◽

...

Keyword(s):

Membrane Trafficking ◽

Secretory Pathway ◽

Secretory Granules ◽

Adaptor Protein ◽

Cell Types ◽

Cellular Membrane ◽

Extracellular Milieu ◽

Specialized Form ◽

Regulated Secretory Pathway ◽

Clathrin Adaptor

ABSTRACTThe regulated secretory pathway is a specialized form of protein secretion found in endocrine and neuroendocrine cell types. Pro-opiomelanocortin (POMC) is a pro-hormone that utilizes this pathway to be trafficked to dense core secretory granules (DCSGs). Within this organelle, POMC is processed to multiple bioactive hormones that play key roles in cellular physiology. However, the complete set of cellular membrane trafficking proteins that mediate the correct sorting of POMC to DCSGs remain unknown. Here, we report the roles of the phosphofurin acidic cluster sorting protein – 1 (PACS-1) and the clathrin adaptor protein 1 (AP-1) in the targeting of POMC to DCSGs. Upon knockdown of PACS-1 and AP-1, POMC is readily secreted into the extracellular milieu and fails to be targeted to DCSGs.

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Phosphoserine acidic cluster motifs in the cytoplasmic domains of transmembrane proteins bind distinct basic regions on the μ subunits of clathrin adaptor protein complexes

10.1101/286633 ◽

2018 ◽

Author(s):

Rajendra Singh ◽

Charlotte Stoneham ◽

Christopher Lim ◽

Xiaofei Jia ◽

Javier Guenaga ◽

...

Keyword(s):

Protein Trafficking ◽

Transmembrane Proteins ◽

Adaptor Protein ◽

Cellular Protein ◽

Membrane Lipid ◽

Dependent Manner ◽

Cytoplasmic Domains ◽

Clathrin Adaptor ◽

Hiv 1

AbstractProtein trafficking in the endosomal system involves the recognition of specific signals within the cytoplasmic domains (CDs) of transmembrane proteins by clathrin adaptors. One such signal is the phosphoserine acidic cluster (PSAC), the prototype of which is in the endoprotease Furin. How PSACs are recognized by clathrin adaptors has been controversial. We reported previously that HIV-1 Vpu, which modulates cellular immunoreceptors, contains a PSAC that binds to the µ subunits of clathrin adaptor protein (AP) complexes. Here, we show that the CD of Furin binds the µ subunits of AP-1 and AP-2 in a phosphorylation-dependent manner. Moreover, we identify a PSAC in a cytoplasmic loop of the cellular transmembrane Serinc3, an inhibitor of the infectivity of retroviruses. The two serines within the PSAC of Serinc3 are phosphorylated by casein kinase II and mediate interaction with the µ subunits in vitro. The sites of these serines vary among mammals in a manner consistent with host-pathogen conflict, yet the Serinc3-PSAC seems dispensible for anti-HIV activity and for counteraction by HIV-1 Nef. The CDs of Vpu, Furin, and the PSAC-containing loop of Serinc3 each bind the μ subunit of AP-2 (µ2) with similar affinities, but they appear to utilize different basic regions on µ2. The Serinc3 loop requires a region previously reported to bind the acidic plasma membrane lipid phosphatidylinositol-4,5-bisphosphate. These data suggest that the PSACs within different proteins recognize different basic regions on the µ surface, providing the potential to inhibit the activity of viral proteins without necessarily affecting cellular protein trafficking.

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The Yeast Clathrin Adaptor Protein Complex 1 Is Required for the Efficient Retention of a Subset of Late Golgi Membrane Proteins

Developmental Cell ◽

10.1016/s1534-5807(02)00127-2 ◽

2002 ◽

Vol 2 (3) ◽

pp. 283-294 ◽

Cited By ~ 157

Author(s):

Raphael H. Valdivia ◽

Daniel Baggott ◽

John S. Chuang ◽

Randy W. Schekman

Keyword(s):

Membrane Proteins ◽

Protein Complex ◽

Adaptor Protein ◽

Golgi Membrane ◽

Clathrin Adaptor

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Axonal transport of mitochondria requires milton to recruit kinesin heavy chain and is light chain independent

The Journal of Cell Biology ◽

10.1083/jcb.200601067 ◽

2006 ◽

Vol 173 (4) ◽

pp. 545-557 ◽

Cited By ~ 368

Author(s):

Elizabeth E. Glater ◽

Laura J. Megeath ◽

R. Steven Stowers ◽

Thomas L. Schwarz

Keyword(s):

Heavy Chain ◽

Light Chain ◽

Adaptor Protein ◽

Direct Interaction ◽

Anterograde Transport ◽

Kinesin Light Chain ◽

Energy Demands ◽

Kinesin Heavy Chain ◽

Conventional Kinesin ◽

Dependent Transport

Mitochondria are distributed within cells to match local energy demands. We report that the microtubule-dependent transport of mitochondria depends on the ability of milton to act as an adaptor protein that can recruit the heavy chain of conventional kinesin-1 (kinesin heavy chain [KHC]) to mitochondria. Biochemical and genetic evidence demonstrate that kinesin recruitment and mitochondrial transport are independent of kinesin light chain (KLC); KLC antagonizes milton's association with KHC and is absent from milton–KHC complexes, and mitochondria are present in klc −/− photoreceptor axons. The recruitment of KHC to mitochondria is, in part, determined by the NH2 terminus–splicing variant of milton. A direct interaction occurs between milton and miro, which is a mitochondrial Rho-like GTPase, and this interaction can influence the recruitment of milton to mitochondria. Thus, milton and miro are likely to form an essential protein complex that links KHC to mitochondria for light chain–independent, anterograde transport of mitochondria.

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Regulation of activity and localization of the WNK1 protein kinase by hyperosmotic stress

The Journal of Cell Biology ◽

10.1083/jcb.200605093 ◽

2006 ◽

Vol 176 (1) ◽

pp. 89-100 ◽

Cited By ~ 119

Author(s):

Anna Zagórska ◽

Eulalia Pozo-Guisado ◽

Jérôme Boudeau ◽

Alberto C. Vitari ◽

Fatema H. Rafiqi ◽

...

Keyword(s):

Mutational Analysis ◽

Adaptor Protein ◽

Hyperosmotic Stress ◽

Recycling Endosomes ◽

Regulation Of Activity ◽

Clathrin Adaptor ◽

Golgi Network ◽

Interfering Rna ◽

Rna Depletion ◽

And Oxidative Stress

Mutations within the WNK1 (with-no-K[Lys] kinase-1) gene cause Gordon's hypertension syndrome. Little is known about how WNK1 is regulated. We demonstrate that WNK1 is rapidly activated and phosphorylated at multiple residues after exposure of cells to hyperosmotic conditions and that activation is mediated by the phosphorylation of its T-loop Ser382 residue, possibly triggered by a transautophosphorylation reaction. Activation of WNK1 coincides with the phosphorylation and activation of two WNK1 substrates, namely, the protein kinases STE20/SPS1-related proline alanine–rich kinase (SPAK) and oxidative stress response kinase-1 (OSR1). Small interfering RNA depletion of WNK1 impairs SPAK/OSR1 activity and phosphorylation of residues targeted by WNK1. Hyperosmotic stress induces rapid redistribution of WNK1 from the cytosol to vesicular structures that may comprise trans-Golgi network (TGN)/recycling endosomes, as they display rapid movement, colocalize with clathrin, adaptor protein complex 1 (AP-1), and TGN46, but not the AP-2 plasma membrane–coated pit marker nor the endosomal markers EEA1, Hrs, and LAMP1. Mutational analysis suggests that the WNK1 C-terminal noncatalytic domain mediates vesicle localization. Our observations shed light on the mechanism by which WNK1 is regulated by hyperosmotic stress.

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