The ALG-2-interacting Protein Alix Associates with CHMP4b, a Human Homologue of Yeast Snf7 That Is Involved in Multivesicular Body Sorting

Katoh, Keiichi; Shibata, Hideki; Suzuki, Hidenori; Nara, Atsuki; Ishidoh, Kazumi; Kominami, Eiki; Yoshimori, Tamotsu; Maki, Masatoshi

doi:10.1074/jbc.m301604200

Cited by 190 publications

(195 citation statements)

References 52 publications

Supporting

Mentioning

184

Contrasting

Order By: Relevance

“…The recent analysis of Bro1-domain structure makes it clear that all Bro1-domain proteins may interact with Snf7 or its orthologues (Kim et al, 2005). Like Snf7 itself (Kranz et al, 2001;Babst et al, 2002), the characterized mammalian Snf7 orthologues have been localized to the endosomal surface and implicated in endosome trafficking (Katoh et al, 2003;Peck et al, 2004;Yorikawa et al, 2005). With that as a backdrop, our finding that Rim20 is localized to Snf7-containing endosomes is entirely expected.…”

Section: Model For Ph-responsive Signal Transductionsupporting

confidence: 50%

“…AIP1/Alix is also required for HIV budding, in which the virus seems to have coopted the MVB formation pathway (Strack et al, 2003;von Schwedler et al, 2003). The Bro1-domain is the site of interaction with a class of vesicle surface proteins such as S. cerevisiae Snf7 or mammalian CHMP4b (Katoh et al, 2003;Kim et al, 2005). Recent studies reveal that Bro1 functions as an adaptor, binding Snf7 to bring the ubiquitin hydrolase Doa4 (Amerik et al, 2000) into proximity with endocytic cargo proteins (Luhtala and Odorizzi, 2004), whose cytoplasmic domains are ubiquitinated (Raiborg et al, 2003;Babst, 2005).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Control of Bro1-Domain Protein Rim20 Localization by External pH, ESCRT Machinery, and theSaccharomyces cerevisiaeRim101 Pathway

Boysen

Mitchell

2006

MBoC

104

View full text Add to dashboard Cite

Bro1-domain proteins such as yeast Bro1 and mammalian AIP1/Alix are well-established participants in endosome metabolism. The Bro1-domain interacts with endosomal surface protein Snf7/Vps32 in yeast, a subunit of the ESCRT complex. Yeast Bro1-domain protein Rim20 has no role in endosome function, but is required for alkaline pH-stimulated cleavage of transcription factor Rim101. Rim20-GFP is cytoplasmic under acidic conditions but concentrated in punctate foci under alkaline conditions. Bro1-GFP also accumulates in foci, but they are more numerous under acidic than alkaline conditions. Colocalization experiments indicate that some Rim20-GFP foci correspond to Bro1-RFP foci, whereas others do not. Rim8, Rim9, Rim21, Dfg16, Snf7, Vps20, Vps23, and Vps25, which are required for Rim101 cleavage, are required for appearance of Rim20-GFP foci. ESCRT complexes accumulate on endosome-derived compartments in cells that lack the AAA-ATPase Vps4. We find that Rim20-GFP foci accumulate in a vps4 mutant background independently of external pH, Rim101 pathway-specific genes, and most ESCRT subunit genes except for SNF7. Rim20-GFP foci seem to represent endosomes, because they colocalize with Snf7-RFP and because they correspond to a perivacuolar compartment in the vps4 strain. We propose that alkaline growth conditions alter the endosomal surface to favor Rim20-Snf7 interaction and Rim101 cleavage. Our findings raise the possibility that Bro1-domain proteins may be differentially regulated in the same cell, thereby coupling endosome metabolism to signaling. INTRODUCTIONAll cells recognize and respond to external signals. For microorganisms, the responses are vital for adaptation to a changeable environment. For multicellular organisms, the responses are critical for coordination of developmental and physiological processes. The plasma membrane is well recognized as the chief sensory organelle of the cell, where receptors undergo environmentally directed changes that relay information to the cytoplasm and nucleus. The endocytic machinery is routinely used for down-regulation of receptors and metabolism or destruction of ligands. However, there is growing evidence that endocytosis plays diverse roles in signal transduction and cell physiology (Di Fiore and De Camilli, 2001;Conner and Schmid, 2003). Recent analysis of the fungal Rim101 pH-response pathway suggests that the endocytic machinery may participate directly in signaling (Kullas et al., 2004;Xu et al., 2004;Barwell et al., 2005;Rothfels et al., 2005). Our focus here is the interaction of endosomal multivesicular body (MVB) formation components with Rim20, a key participant in pH-dependent signaling.Rim20 is required for proteolytic activation of the transcription factor Rim101 . Rim101 cleavage removes a ϳ100-residue C-terminal PEST-like region, allowing the N-terminal zinc finger region to effect transcriptional changes (Li and Mitchell, 1997;Lamb et al., 2001). Ultimately, cleaved Rim101 is required for expression of many alkaline pH-inducible genes (Lamb et al., 2001...

show abstract

Section: Model For Ph-responsive Signal Transductionsupporting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

Control of Bro1-Domain Protein Rim20 Localization by External pH, ESCRT Machinery, and theSaccharomyces cerevisiaeRim101 Pathway

Boysen

Mitchell

2006

MBoC

104

View full text Add to dashboard Cite

show abstract

“…This region was shown to interact with SETA (SH3 domain expressed in tumorigenic astrocytes) (8), whereby Alix/ AIP1 could mediate UV light-induced cell death in astrocytes. Alix/AIP1 has also been implicated in multivesicular sorting mediated by the interactions of the N-terminal region of the protein with CHMP4b (9), while the C-terminal region is associated with ALG-2 interactions. It has been proposed that Alix/AIP1 could form a molecular link between endosomal sorting and cell death pathways (10).…”

mentioning

confidence: 99%

Ca²⁺ Binding to EF Hands 1 and 3 Is Essential for the Interaction of Apoptosis-Linked Gene-2 with Alix/AIP1 in Ocular Melanoma

et al. 2004

View full text Add to dashboard Cite

Apoptosis-linked gene-2 (ALG-2) encodes a 22 kDa Ca 2+ -binding protein of the penta EF-hand family that is required for programmed cell death in response to various apoptotic agents. Here, we demonstrate that ALG-2 mRNA and protein are down-regulated in human uveal melanoma cells compared to their progenitor cells, normal melanocytes. The down regulation of ALG-2 may provide melanoma cells with a selective advantage. ALG-2 and its putative target molecule, Alix/AIP1, are localized primarily in the cytoplasm of melanocytes and melanoma cells independent of the intracellular Ca 2+ concentration or the activation of apoptosis. Cross-linking and analytical centrifugation studies support a single-species dimer conformation of ALG-2, also independent of Ca 2+ concentration. However, binding of Ca 2+ to both EF-1 and EF-3 is necessary for ALG-2 interaction with Alix/AIP1 as demonstrated using surface plasmon resonance spectroscopy. Mutations in EF-5 result in reduced target interaction without alteration in Ca 2+ affinity. The addition of N-terminal ALG-2 peptides, residues 1-22 or residues 7-17, does not alter the interaction of ALG-2 or an N-terminal deletion mutant of ALG-2 with Alix/AIP1, as might be expected from a model derived from the crystal structure of ALG-2. Fluorescence studies of ALG-2 demonstrate that an increase in surface hydrophobicity is primarily due to Ca 2+ binding to EF-3, while Ca 2+ binding to EF-1 has little effect on surface exposure of hydrophobic residues. Together, these data indicate that gross surface hydrophobicity changes are insufficient for target recognition. † This work was supported by NIH Grants EY12768 and EY13705 (A.S.P.), EY08061 (K.P.), and EY06603 and EY14239 (J.W.C.) and the Swiss National Science Foundation 31-65071.01 (J.C.), as well as grants from the Retina Research Foundation, Research to Prevent Blindness Inc. (RPB), the University of Wisconsin Comprehensive Cancer Center, and the E. K. Bishop Foundation. L.S. is a recipient of the Cremer Scholarship. A.S.P. is a Jules and Doris Stein RPB Professor. * To whom correspondence should be addressed. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptApoptosis-linked gene-2 (ALG-2) was first identified in a death-trap assay using a mouse T cell hybridoma model (1). These cells when transfected with an antisense ALG-2 expression vector were resistant to T cell receptor-mediated cell death and were partially protected from other agents that normally initiate programmed cell death such as Fas, staurosporine, actinomycin D, and C 2 -ceramide (1). More recent work suggests that ALG-2 might be involved in the apaf1-independent intrinsic apoptotic pathway activated as a result of endoplasmic reticulum (ER) stress (2).ALG-2 contains five putative EF-hand sequences and is a member of the family of PEF 1 (penta-EF-hand) proteins that includes the calpain small subunit, sorcin, and grancalcin (3). In ALG-2, EF-1 and EF-3 are considered the high-affinity Ca 2+ -binding sites, while one low-affinity site...

show abstract

“…The different ESCRT-III proteins apparently adopt similar folds (6) and can copolymerize together on membranes, yet have evolved to interact differently with other ESCRT pathway components. For example, only the three human CHMP4 proteins (CHMP4A-C) can bind ALIX (yeast Bro1p), another protein in the ESCRT pathway (7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”

mentioning

confidence: 99%

ALIX-CHMP4 interactions in the human ESCRT pathway

McCullough

Fisher

Whitby

et al. 2008

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

212

252

View full text Add to dashboard Cite

The ESCRT pathway facilitates membrane fission events during enveloped virus budding, multivesicular body formation, and cytokinesis. To promote HIV budding and cytokinesis, the ALIX protein must bind and recruit CHMP4 subunits of the ESCRT-III complex, which in turn participate in essential membrane remodeling functions. Here, we report that the Bro1 domain of ALIX binds specifically to C-terminal residues of the human CHMP4 proteins (CHMP4A-C). Crystal structures of the complexes reveal that the CHMP4 C-terminal peptides form amphipathic helices that bind across the conserved concave surface of ALIXBro1. ALIX-dependent HIV-1 budding is blocked by mutations in exposed ALIXBro1 residues that help contribute to the binding sites for three essential hydrophobic residues that are displayed on one side of the CHMP4 recognition helix (M/L/IxxLxxW). The homologous CHMP1-3 classes of ESCRT-III proteins also have C-terminal amphipathic helices, but, in those cases, the three hydrophobic residues are arrayed with L/I/MxxxLxxL spacing. Thus, the distinct patterns of hydrophobic residues provide a ''code'' that allows the different ESCRT-III subunits to bind different ESCRT pathway partners, with CHMP1-3 proteins binding MIT domain-containing proteins, such as VPS4 and Vta1/LIP5, and CHMP4 proteins binding Bro1 domaincontaining proteins, such as ALIX.cytokinesis ͉ ESCRT-III ͉ HIV ͉ mutivesicular body

show abstract

The ALG-2-interacting Protein Alix Associates with CHMP4b, a Human Homologue of Yeast Snf7 That Is Involved in Multivesicular Body Sorting

Cited by 190 publications

References 52 publications

Control of Bro1-Domain Protein Rim20 Localization by External pH, ESCRT Machinery, and theSaccharomyces cerevisiaeRim101 Pathway

Control of Bro1-Domain Protein Rim20 Localization by External pH, ESCRT Machinery, and theSaccharomyces cerevisiaeRim101 Pathway

Ca²⁺ Binding to EF Hands 1 and 3 Is Essential for the Interaction of Apoptosis-Linked Gene-2 with Alix/AIP1 in Ocular Melanoma

ALIX-CHMP4 interactions in the human ESCRT pathway

Contact Info

Product

Resources

About

The ALG-2-interacting Protein Alix Associates with CHMP4b, a Human Homologue of Yeast Snf7 That Is Involved in Multivesicular Body Sorting

Cited by 190 publications

References 52 publications

Control of Bro1-Domain Protein Rim20 Localization by External pH, ESCRT Machinery, and theSaccharomyces cerevisiaeRim101 Pathway

Control of Bro1-Domain Protein Rim20 Localization by External pH, ESCRT Machinery, and theSaccharomyces cerevisiaeRim101 Pathway

Ca2+ Binding to EF Hands 1 and 3 Is Essential for the Interaction of Apoptosis-Linked Gene-2 with Alix/AIP1 in Ocular Melanoma

ALIX-CHMP4 interactions in the human ESCRT pathway

Contact Info

Product

Resources

About

Ca²⁺ Binding to EF Hands 1 and 3 Is Essential for the Interaction of Apoptosis-Linked Gene-2 with Alix/AIP1 in Ocular Melanoma