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.

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.

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.

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

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 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.

Three-dimensional structure of an fab-peptide complex: structural basis of HIV-1 protease inhibition by a monoclonal antibody

1997 ◽  
Vol 267 (5) ◽  
pp. 1207-1222 ◽  
Author(s):  
Julien Lescar ◽  
Renata Stouracova ◽  
Marie-Madeleine Riottot ◽  
Véronique Chitarra ◽  
Jiri Brynda ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Structural Basis ◽  
Protease Inhibition ◽  
Peptide Complex ◽  
Three Dimensional Structure ◽  
Complex Structural ◽  
Hiv 1

Alix and ALG-2 make a link between endosomes and neuronal death

2009 ◽  
Vol 37 (1) ◽  
pp. 200-203 ◽  
Author(s):  
Anne-Laure Mahul-Mellier ◽  
Flavie Strappazzon ◽  
Christine Chatellard-Causse ◽  
Béatrice Blot ◽  
David Béal ◽  
...  
Keyword(s):  
Neuronal Death ◽  
Calcium Binding ◽  
Death Receptor ◽  
Adaptor Protein ◽  
Endosomal Trafficking ◽  
Interacting Protein ◽  
Linked Gene ◽  
Endosomal Sorting ◽  
Factor Α ◽  
Necrosis Factor

Alix [ALG-2 (apoptosis-linked gene 2)-interacting protein X] is a ubiquitinous adaptor protein first described for its capacity to bind to the calcium-binding protein, ALG-2. Alix regulates neuronal death in ways involving interactions with ALG-2 and with proteins of the ESCRT (endosomal sorting complex required for transport). Even though all Alix interactors characterized to date are involved in endosomal trafficking, the genuine function of the protein in this process remains unclear. We have demonstrated recently that Alix and ALG-2 form in the presence of calcium, a complex with apical caspases and with the endocytosed death receptor TNFR1 (tumour necrosis factor α receptor 1), thus suggesting a molecular coupling between endosomes and the cell death machinery.

3D-QSAR Studies of S-DABO Derivatives as Non-nucleoside HIV-1 Reverse Transcriptase Inhibitors

2019 ◽  
Vol 16 (8) ◽  
pp. 868-881
Author(s):  
Yueping Wang ◽  
Jie Chang ◽  
Jiangyuan Wang ◽  
Peng Zhong ◽  
Yufang Zhang ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Three Dimensional ◽  
Predictive Ability ◽  
3D Qsar ◽  
Binding Mode ◽  
Quantitative Structure Activity Relationship ◽  
Field Analysis ◽  
Reverse Transcriptase Inhibitors ◽  
Qsar Studies ◽  
Hiv 1

Background: S-dihydro-alkyloxy-benzyl-oxopyrimidines (S-DABOs) as non-nucleoside reverse transcriptase inhibitors have received considerable attention during the last decade due to their high potency against HIV-1. Methods: In this study, three-dimensional quantitative structure-activity relationship (3D-QSAR) of a series of 38 S-DABO analogues developed in our lab was studied using Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA). The Docking/MMFF94s computational protocol based on the co-crystallized complex (PDB ID: 1RT2) was used to determine the most probable binding mode and to obtain reliable conformations for molecular alignment. Statistically significant CoMFA (q2=0.766 and r2=0.949) and CoMSIA (q2=0.827 and r2=0.974) models were generated using the training set of 30 compounds on the basis of hybrid docking-based and ligand-based alignment. Results: The predictive ability of CoMFA and CoMSIA models was further validated using a test set of eight compounds with predictive r2 pred values of 0.843 and 0.723, respectively. Conclusion: The information obtained from the 3D contour maps can be used in designing new SDABO derivatives with improved HIV-1 inhibitory activity.

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