scholarly journals The Adaptor Protein Alix is Involved in the Interaction Between the Ubiquitin Ligase NEDD4-1 and its Targets, ABCG1 and ABCG4

2019 ◽  
Vol 20 (11) ◽  
pp. 2714 ◽  
Author(s):  
Amjad Alrosan ◽  
Shereen M. Aleidi ◽  
Alryel Yang ◽  
Andrew J. Brown ◽  
Ingrid C. Gelissen
Keyword(s):  
Ubiquitin Ligase ◽  
Abc Transporters ◽  
Adaptor Protein ◽  
Interacting Protein ◽  
Linked Gene ◽  
Transporter Protein ◽  
Peptide Mass ◽  
Protein X ◽  
Peptide Mass Spectrometry ◽  
Gene 4

Several ATP-Binding Cassette (ABC) transporters, including ABCG1 and the related ABCG4, are essential regulators of cellular lipid homeostasis. ABCG1 is expressed ubiquitously and is functional in the context of atherosclerosis. However, ABCG4 is expressed almost exclusively in brain and has been linked to Alzheimer’s disease (AD). These transporters are highly regulated post-translationally by E3 ubiquitin ligases, with the ligase NEDD4-1 (Neural precursor cell-expressed developmentally downregulated gene 4) implicated in their protein stability. In this study, we investigated interacting partners of ABCG1 using peptide-mass spectrometry and identified the potential adaptor protein, Alix (apoptosis-linked gene 2-interacting protein X). In this paper, we hypothesized and investigated whether Alix could facilitate the interaction between NEDD4-1 and the ABC transporters. We showed that Alix and NEDD4-1 proteins were co-expressed in several commonly used cell lines. Knockdown of Alix in cells overexpressing ABCG1 or ABCG4 increased transporter protein expression while co-immunoprecipitation experiments showed interaction between NEDD4-1, Alix, and ABC transporters. In summary, we provide evidence that Alix serves as a co-factor for the interaction between the E3-ubiquitin ligase NEDD4-1 and the ABC transporter targets, ABCG1 and ABCG4.

Dengue virus requires apoptosis linked gene-2-interacting protein X (ALIX) for viral propagation

2019 ◽  
Vol 261 ◽  
pp. 65-71 ◽  
Author(s):  
Chutima Thepparit ◽  
Sarawut Khongwichit ◽  
Kunjimas Ketsuwan ◽  
Sirikwan Libsittikul ◽  
Prasert Auewarakul ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Interacting Protein ◽  
Linked Gene ◽  
Viral Propagation ◽  
Protein X

The ESCRT pathway and HIV-1 budding

2009 ◽  
Vol 37 (1) ◽  
pp. 181-184 ◽  
Author(s):  
Yoshiko Usami ◽  
Sergei Popov ◽  
Elena Popova ◽  
Michio Inoue ◽  
Winfried Weissenhorn ◽  
...  
Keyword(s):  
Susceptibility Gene ◽  
Multivesicular Body ◽  
Intramolecular Interactions ◽  
Transport Pathway ◽  
Interacting Protein ◽  
Linked Gene ◽  
Endosomal Sorting ◽  
Binding Partner ◽  
Protein X ◽  
Hiv 1

HIV-1 Gag engages components of the ESCRT (endosomal sorting complex required for transport) pathway via so-called L (late-assembly) domains to promote virus budding. Specifically, the PTAP (Pro-Thr-Ala-Pro)-type primary L domain of HIV-1 recruits ESCRT-I by binding to Tsg101 (tumour susceptibility gene 101), and an auxiliary LYPXnL (Leu-Tyr-Pro-Xaan-Leu)-type L domain recruits the ESCRT-III-binding partner Alix [ALG-2 (apoptosis-linked gene 2)-interacting protein X]. The structurally related CHMPs (charged multivesicular body proteins), which form ESCRT-III, are kept in an inactive state through intramolecular interactions, and become potent inhibitors of HIV-1 budding upon removal of an autoinhibitory region. In the absence of the primary L domain, HIV-1 budding is strongly impaired, but can be efficiently rescued through the overexpression of Alix. This effect of Alix depends on its ability to interact with CHMP4, suggesting that it is the recruitment of CHMPs that ultimately drives virus release. Surprisingly, HIV-1 budding defects can also be efficiently corrected by overexpressing Nedd (neural-precursor-cell-expressed developmentally down-regulated) 4-2s, a member of a family of ubiquitin ligases previously implicated in the function of PPXY (Pro-Pro-Xaa-Tyr)-type L domains, which are absent from HIV-1. At least under certain circumstances, Nedd4-2s stimulates the activity of PTAP-type L domains, raising the possibility that the ubiquitin ligase regulates the activity of ESCRT-I.

Early increase of apoptosis-linked gene-2 interacting protein X in areas of kainate-induced neurodegeneration

Neuroscience ◽  
2004 ◽  
Vol 123 (4) ◽  
pp. 887-895 ◽  
Author(s):  
F.J Hemming ◽  
S Fraboulet ◽  
B Blot ◽  
R Sadoul
Keyword(s):  
Interacting Protein ◽  
Linked Gene ◽  
Protein X ◽  
Early Increase

Increased Alix (apoptosis-linked gene-2 interacting protein X) immunoreactivity in the degenerating striatum of rats chronically treated by 3-nitropropionic acid

2004 ◽  
Vol 368 (3) ◽  
pp. 309-313 ◽  
Author(s):  
David Blum ◽  
Fiona J. Hemming ◽  
Marie-Christine Galas ◽  
Sakina Torch ◽  
Laetitia Cuvelier ◽  
...  
Keyword(s):  
Interacting Protein ◽  
Linked Gene ◽  
Nitropropionic Acid ◽  
Protein X ◽  
3 Nitropropionic Acid

scholarly journals The E3 Ubiquitin Ligase Atrophin Interacting Protein 4 Binds Directly To The Chemokine Receptor CXCR4 Via a Novel WW Domain-mediated Interaction

2009 ◽  
Vol 20 (5) ◽  
pp. 1324-1339 ◽  
Author(s):  
Deepali Bhandari ◽  
Seth L. Robia ◽  
Adriano Marchese
Keyword(s):  
Ubiquitin Ligase ◽  
Chemokine Receptor ◽  
E3 Ubiquitin Ligase ◽  
Adaptor Protein ◽  
Interacting Protein ◽  
Binding Motifs ◽  
Ww Domain ◽  
Ww Domains ◽  
Chemokine Receptor Cxcr4 ◽  
Carboxy Terminal

The E3 ubiquitin ligase atrophin interacting protein 4 (AIP4) mediates ubiquitination and down-regulation of the chemokine receptor CXCR4. AIP4 belongs to the Nedd4-like homologous to E6-AP carboxy terminus domain family of E3 ubiquitin ligases, which typically bind proline-rich motifs within target proteins via the WW domains. The intracellular domains of CXCR4 lack canonical WW domain binding motifs; thus, whether AIP4 is targeted to CXCR4 directly or indirectly via an adaptor protein remains unknown. Here, we show that AIP4 can interact directly with CXCR4 via a novel noncanonical WW domain-mediated interaction involving serine residues 324 and 325 within the carboxy-terminal tail of CXCR4. These serine residues are critical for mediating agonist-promoted binding of AIP4 and subsequent ubiquitination and degradation of CXCR4. These residues are phosphorylated upon agonist activation and phosphomimetic mutants show enhanced binding to AIP4, suggesting a mechanism whereby phosphorylation mediates the interaction between CXCR4 and AIP4. Our data reveal a novel noncanonical WW domain-mediated interaction involving phosphorylated serine residues in the absence of any proline residues and suggest a novel mechanism whereby an E3 ubiquitin ligase is targeted directly to an activated G protein-coupled receptor.

The CHMP4b- and Src-docking sites in the Bro1 domain are autoinhibited in the native state of Alix

2009 ◽  
Vol 418 (2) ◽  
pp. 277-284 ◽  
Author(s):  
Xi Zhou ◽  
Shujuan Pan ◽  
Le Sun ◽  
Joe Corvera ◽  
Yu-Chen Lee ◽  
...  
Keyword(s):  
Multivesicular Body ◽  
Human Embryonic Kidney ◽  
Native State ◽  
Interacting Protein ◽  
Body Protein ◽  
Linked Gene ◽  
Endosomal Sorting ◽  
Protein X ◽  
Membrane Bound ◽  
Docking Sites

The Bro1 domain of Alix [ALG-2 (apoptosis-linked gene 2)-interacting protein X], which plays important roles in endosomal sorting and multiple ESCRT (endosomal sorting complex required for transport)-linked processes, contains the docking sites for the ESCRT-III component CHMP4b (charged multivesicular body protein 4b) and the regulatory tyrosine kinase, Src. Although the structural bases for these docking sites have been defined by crystallography studies, it has not been determined whether these sites are available in the native state of Alix. In the present study, we demonstrate that these two docking sites are unavailable in recombinant Alix under native conditions and that their availabilities can be induced by detergents. In HEK (human embryonic kidney)-293 cell lysates, these two docking sites are not available in cytosolic Alix, but are available in membrane-bound Alix. These findings show that the native state of Alix does not have a functional Bro1 domain and predict that Alix's involvement in endosomal sorting and other ESCRT-linked processes requires an activation step that relieves the autoinhibition of the Bro1 domain.

The mechanism of Ca2+-dependent recognition of Alix by ALG-2: insights from X-ray crystal structures

2009 ◽  
Vol 37 (1) ◽  
pp. 190-194 ◽  
Author(s):  
Hironori Suzuki ◽  
Masato Kawasaki ◽  
Tatsutoshi Inuzuka ◽  
Mayumi Okumura ◽  
Takeshi Kakiuchi ◽  
...  
Keyword(s):  
Tandem Repeats ◽  
Susceptibility Gene ◽  
Adaptor Protein ◽  
Side Chain ◽  
Interacting Protein ◽  
Linked Gene ◽  
X Ray ◽  
Ef Hand ◽  
Peptide Binding Site ◽  
Crystal Structural

Alix [ALG-2 (apoptosis-linked gene 2)-interacting protein X] was originally identified as a protein that interacts with ALG-2, a member of the penta-EF-hand Ca2+-binding protein family. ALG-2 binds to its C-terminal proline-rich region that contains four tandem repeats of PXY (where X represents an uncharged amino acid). Recent X-ray crystal structural analyses of the Ca2+-free and Ca2+-bound forms of ALG-2, as well as the complex with an Alix oligopeptide, have revealed a mechanism of Ca2+-dependent binding of ALG-2 to its target protein. Binding of Ca2+ to EF3 (third EF-hand) enables the side chain of Arg125, present in the loop connecting EF3 and EF4 (fourth EF-hand), to move sufficiently to make a primary hydrophobic pocket accessible to the critical PPYP (Pro-Pro-Tyr-Pro) motif in Alix, which partially overlaps with the GPP (Gly-Pro-Pro) motif for binding to Cep55 (centrosome protein of 55 kDa). The fact that ALG-2 forms a homodimer and each monomer has one peptide-binding site indicates the possibility that ALG-2 bridges two interacting proteins, including Alix and Tsg101 (tumour susceptibility gene 101), and functions as a Ca2+-dependent adaptor protein.

scholarly journals ALG-2 interacting protein-X (Alix) is required for activity-dependent bulk endocytosis at brain synapses

2020 ◽  
Author(s):  
Marine H. Laporte ◽  
Kwang Il Chi ◽  
Marta Rolland ◽  
Laura C. Caudal ◽  
José Martinez-Hernandez ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Epileptiform Activity ◽  
Adaptor Protein ◽  
Contralateral Side ◽  
High Frequency Stimulation ◽  
Interacting Protein ◽  
Protein X ◽  
Frequency Stimulation ◽  
Chemical Synapses ◽  
Activity Dependent

AbstractIn chemical synapses undergoing high frequency stimulation, vesicle components can be retrieved from the plasma membrane via a clathrin-independent process called activity dependent bulk endocytosis (ADBE). Alix (ALG-2 interacting protein X)/ PDCD6IP) is an adaptor protein binding to ESCRT and endophilin-A proteins and thereby driving deformation and fission of endosomal and cell surface membranes. In fibroblasts, Alix is required for clathrin-independent endocytosis. Here, using electron microscopy, we show that synapses from mice lacking Alix have subtle defects in presynaptic compartments, translating into flawed synaptic plasticity. Using cultured neurons, we demonstrate that Alix is required for ADBE. We further demonstrate that in order to perform ADBE, Alix must be recruited to synapses by the calcium-binding protein ALG-2 and interact with endophilin-A. Finally, we show that mutant mice lacking Alix in the forebrain undergo less seizures during kainate-induced status epilepticus. Furthermore, propagation of the epileptiform activity to the contralateral side of kainate injection is reduced. These results thus highlight Alix ko mice as an invaluable model to study the exact role of ADBE at synapses undergoing physiological or pathological stimulations.

The HIV-1 p6/EIAV p9 docking site in Alix is autoinhibited as revealed by a conformation-sensitive anti-Alix monoclonal antibody

2008 ◽  
Vol 414 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Xi Zhou ◽  
Shujuan Pan ◽  
Le Sun ◽  
Joe Corvera ◽  
Sue-Hwa Lin ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Three Dimensional ◽  
Docking Site ◽  
Positive Role ◽  
Interacting Protein ◽  
Linked Gene ◽  
Endosomal Sorting ◽  
Protein X ◽  
Equine Infectious Anaemia Virus ◽  
Hiv 1

Alix [ALG-2 (apoptosis-linked gene 2)-interacting protein X], a component of the endosomal sorting machinery, contains a three-dimensional docking site for HIV-1 p6Gag or EIAV (equine infectious anaemia virus) p9Gag, and binding of the viral protein to this docking site allows the virus to hijack the host endosomal sorting machinery for budding from the plasma membrane. In the present study, we identified a monoclonal antibody that specifically recognizes the docking site for p6Gag/p9Gag and we used this antibody to probe the accessibility of the docking site in Alix. Our results show that the docking site is not available in cytosolic or recombinant Alix under native conditions and becomes available upon addition of the detergent Nonidet P40 or SDS. In HEK (human embryonic kidney)-293 cell lysates, an active p6Gag/p9Gag docking site is specifically available in Alix from the membrane fraction. The findings of the present study demonstrate that formation or exposure of the p6Gag/p9Gag docking site in Alix is a regulated event and that Alix association with the membrane may play a positive role in this process.

Sign in / Sign up

Export Citation Format

Share Document