Exploring the functional interaction between POSH and ALIX and the relevance to HIV-1 release

Votteler, Jörg; Iavnilovitch, Elena; Fingrut, Orit; Shemesh, Vivian; Taglicht, Daniel; Erez, Omri; Sörgel, Stefan; Walther, Torsten; Bannert, Norbert; Schubert, Ulrich S.; Reiss, Yuval

doi:10.1186/1742-4690-6-s2-p92

Cited by 7 publications

(7 citation statements)

References 5 publications

(6 reference statements)

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“…Furthermore, a TGN-associated E3-ubiquitin ligase POSH has been shown to be essential for targeting Pr55 gag to the plasma membrane and virus release (Alroy et al 2005) suggesting that ubiquitination of Pr55 gag or other cellular substrates may regulate productive assembly at multiple levels. In accordance with this, a recent report suggested that ALIX/AIP1 is a substrate for POSH and ubiquitination of ALIX/AIP1by POSH may play an auxiliary role in facilitating HIV-1 release (Votteler et al 2009).…”

Section: Role Of Ubiquitin Ligases In Hiv-1 Buddingsupporting

confidence: 57%

The Vpu-regulated endocytosis of HIV-1 Gag is clathrin-independent

et al. 2007

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Recent results by us and others have shown that the accessory protein Vpu determines plasma membrane versus endosomal accumulation of the HIV-1 core protein Gag and progeny virions in the HeLa model of HIV-1 infection, since Vpu suppresses endocytosis of cell surface-associated Gag. In this report, we used pulse-chase studies and subcellular fractionations to investigate endocytosis of newly synthesized Gag in HeLa H1 cells. The uptake of Gag in Delta Vpu-virus background was not blocked by inhibitors of clathrin-mediated endocytosis and macropinocytosis. The cholesterol-sequestering drug filipin inhibited the uptake, but only if the drug was applied before extensive multimerization of Gag had taken place. Thus, the uptake mechanism most likely is only indirectly dependent on cholesterol. Our results also indicated that targeting phenotype of Gag was different in confluent versus subconfluent cell cultures, which could perhaps explain some of the controversies in intracellular targeting of Gag.

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Section: Role Of Ubiquitin Ligases In Hiv-1 Buddingsupporting

confidence: 57%

The Vpu-regulated endocytosis of HIV-1 Gag is clathrin-independent

et al. 2007

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“…Gag proteins carrying PPxY motifs also undergo ubiquitination (149). In addition, HIV‐1 and feline immune deficiency virus (FIV), which do not use PPxY motifs that directly bind HECT domain ligases, are also stimulated by overexpression of Ub ligases, especially when their direct connection with ESCRT‐I is severed (116,150–152). Like the PPxY motif, the HIV‐1 late domain motifs can also mediate ubiquitination of Gag proteins in some circumstances (150).…”

Section: Ub and Escrt‐dependent Viral Buddingmentioning

confidence: 99%

How Ubiquitin Functions with ESCRTs

Shields¹,

Piper²

2011

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The ESCRT apparatus has multiple Ubiquitin-binding domains and participates in a wide variety of cellular processes. Many of these ESCRT-dependent processes are keenly regulated by Ub, which serves as a lysosomal sorting signal for membrane proteins targeted into multivesicular bodies and which may serve as a mediator of viral budding from the cell surface. Hints that both ESCRTs and Ub work together in the processes such as cytokinesis, transcription, and autophagy are beginning to emerge. Here we explore the relationship between ESCRTs and Ub in MVB sorting and viral budding.

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“…In a recent paper by Votteler et al [18] the authors found that ALIX‐mediated release of infectious HIV virions was enhanced by POSH1 although silencing of POSH1 by RNAi did not have the anticipated opposing effect. In the light of the presence of three POSH proteins in mammalian cells it is however possible that knockdown of all POSH family members would give the expected results.…”

Section: Resultsmentioning

confidence: 97%

POSH2 is a RING finger E3 ligase with Rac1 binding activity through a partial CRIB domain

Kärkkäinen¹,

Linden²,

Renkema³

2010

FEBS Letters

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Edited by Gianni Cesareni Keywords:Plenty of SH3 domains Src homology 3 p21-Activated kinase CRIB domain E3 ligase a b s t r a c tThe Plenty of SH3 domains protein (POSH) is an E3 ligase and a scaffold in the JNK mediated apoptosis, linking Rac1 to downstream components.We here describe POSH2 which was identified from a p21-activated kinase 2 (PAK2) interactor screen. POSH2 is highly homologous with other members of the POSH family; it contains four Src homology 3 (SH3) domains and a RING finger domain which confers E3 ligase activity to the protein.In addition POSH2 contains an N-terminal extension which is conserved among its mammalian counterparts. POSH2 interacts with GTP-loaded Rac1. We have mapped this interaction to a previously unrecognized partial Cdc42/Rac1-interactive binding domain.

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Exploring the functional interaction between POSH and ALIX and the relevance to HIV-1 release

Cited by 7 publications

References 5 publications

The Vpu-regulated endocytosis of HIV-1 Gag is clathrin-independent

The Vpu-regulated endocytosis of HIV-1 Gag is clathrin-independent

How Ubiquitin Functions with ESCRTs

POSH2 is a RING finger E3 ligase with Rac1 binding activity through a partial CRIB domain

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