PalC, One of Two Bro1 Domain Proteins in the Fungal pH Signalling Pathway, Localizes to Cortical Structures and Binds Vps32

Galindo, Antonio; Hervás-Aguilar, América; Rodríguez-Galán, Olga; Vincent, Olivier; Arst, Herbert N.; Tilburn, Joan; Peñalva, Miguel

doi:10.1111/j.1600-0854.2007.00620.x

Cited by 67 publications

(93 citation statements)

References 72 publications

(142 reference statements)

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“…The latter correspond to a conserved multifunctional class of proteins extensively studied in yeast (represented by Bro1 and Rim20) and animals (ALIX), where they associate with ESCRT-III complex by interacting with their Snf7/ Vps32/CHMP4 subunit and facilitate cargo sorting and ILV formation (Galindo et al, 2007;McCullough et al, 2008;Wemmer et al, 2011;Bissig and Gruenberg, 2014). Mutations impairing Bro1-Snf7 interaction severely inhibit ILV formation and cargo sorting in yeast, therefore altering trafficking and degradation of protein cargoes at the lytic vacuoles.…”

Section: Introductionmentioning

confidence: 99%

ESCRT-III-Associated Protein ALIX Mediates High-Affinity Phosphate Transporter Trafficking to Maintain Phosphate Homeostasis in Arabidopsis

et al. 2015

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ORCID IDs: 0000-0003-2780-4888 (C.R.); 0000-0002-8800-2400 (V.R.)Prior to the release of their cargoes into the vacuolar lumen, sorting endosomes mature into multivesicular bodies (MVBs) through the action of ENDOSOMAL COMPLEX REQUIRED FOR TRANSPORT (ESCRT) protein complexes. MVB-mediated sorting of high-affinity phosphate transporters (PHT1) to the vacuole limits their plasma membrane levels under phosphatesufficient conditions, a process that allows plants to maintain phosphate homeostasis. Here, we describe ALIX, a cytosolic protein that associates with MVB by interacting with ESCRT-III subunit SNF7 and mediates PHT1;1 trafficking to the vacuole in Arabidopsis thaliana. We show that the partial loss-of-function mutant alix-1 displays reduced vacuolar degradation of PHT1;1. ALIX derivatives containing the alix-1 mutation showed reduced interaction with SNF7, providing a simple molecular explanation for impaired cargo trafficking in alix-1 mutants. In fact, the alix-1 mutation also hampered vacuolar sorting of the brassinosteroid receptor BRI1. We also show that alix-1 displays altered vacuole morphogenesis, implying a new role for ALIX proteins in vacuolar biogenesis, likely acting as part of ESCRT-III complexes. In line with a presumed broad target spectrum, the alix-1 mutation is pleiotropic, leading to reduced plant growth and late flowering, with stronger alix mutations being lethal, indicating that ALIX participates in diverse processes in plants essential for their life. INTRODUCTIONTrafficking of cargo proteins coming from the plasma membrane (PM) or the Golgi apparatus (GA) to the vacuole occurs through multivesicular bodies (MVBs) (Winter and Hauser, 2006). These organelles, also termed late endosomes or prevacuolar compartments (PVCs), contain internal vesicles that will be delivered, together with their cargoes, into the lumen of vacuoles/lysosomes upon MVB fusion with the tonoplast (Winter and Hauser, 2006). This process plays a central role in controlling the reutilization, storage, or degradation of membrane components and thus regulates fundamental biological processes including membrane turnover, defense against pathogens, development, hormone transport, nutrient uptake, and cell signaling. In the case of membrane-associated regulatory proteins, the MVB route allows modulation of their function by regulating their abundance at the PM and in other vesicular compartments (e.g., endosomes).The sorting of most integral membrane proteins into intraluminal vesicles (ILVs) is dependent on the attachment of ubiquitin to their cytosolic domains, although ubiquitin-independent sorting mechanisms also exist (McNatt et al., 2007). Selective packaging of protein cargoes into ILVs of MVB is mediated by ESCRT (ENDOSOMAL SORTING COMPLEXES REQUIRED FOR TRANSPORT) protein complexes (Conibear, 2002;Winter and Hauser, 2006;Nickerson et al., 2007;Henne et al., 2011). The latter consist of several cytosolic proteins of the VPS-E (class E Vacuolar Protein Sorting) class that are organized into five complexes: ESCRT-0...

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Section: Introductionmentioning

confidence: 99%

ESCRT-III-Associated Protein ALIX Mediates High-Affinity Phosphate Transporter Trafficking to Maintain Phosphate Homeostasis in Arabidopsis

et al. 2015

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“…A third possibility is that the C-terminal group C cluster interacts with an unidentified Rim101 pathway member in C. albicans. In A. nidulans, Yarrowia lipolytica, and S. cerevisiae, an additional Rim101 pathway member, PalC/ Rim23, has been identified which contains a bro1-domain and is able to interact with Snf7 (Tilburn et al 2005;Galindo et al 2007;Blanchin-Roland et al 2008). We identified C. albicans orf19.2914 through a blast search with ScRim23 sequence.…”

Section: Discussionmentioning

confidence: 99%

Mutational Analysis of Candida albicans SNF7 Reveals Genetically Separable Rim101 and ESCRT Functions and Demonstrates Divergence in bro1-Domain Protein Interactions

Wolf

Davis²

2010

Genetics

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The opportunistic pathogen Candida albicans can grow over a wide pH range, which is associated with its ability to colonize and infect distinct host niches. C. albicans growth in neutral-alkaline environments requires proteolytic activation of the transcription factor Rim101. Rim101 activation requires Snf7, a member of the endosomal sorting complex required for transport (ESCRT) pathway. We hypothesized that Snf7 has distinct functions in the Rim101 and ESCRT pathways, which we tested by alanine-scanning mutagenesis. While some snf7 alleles conferred no defects, we identified alleles with solely ESCRTdependent, solely Rim101-dependent, or both Rim101-and ESCRT-dependent defects. Thus, Snf7 function in these two pathways is at least partially separable. Both Rim101-and ESCRT-dependent functions require Snf7 recruitment to the endosomal membrane and alleles that disrupted both pathways were found to localize normally, suggesting a downstream defect. Most alleles that conferred solely Rim101-dependent defects were still able to process Rim101 normally under steady-state conditions. However, these same strains did display a kinetic defect in Rim101 processing. Several alleles with solely Rim101-dependent defects mapped to the C-terminal end of Snf7. Further analyses suggested that these mutations disrupted interactions with bro-domain proteins, Rim20 and Bro1, in overlapping but slightly divergent Snf7 domains.

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“…Recent work with both A. nidulans and S. cerevisiae has dramatically changed this situation and has revealed an unexpected additional role in pH signal transduction for most, but not all, of the components of the multivesicular body pathway cargo-sorting protein complexes (6,16,18,19,42,(52)(53)(54). Two A. nidulans pH signaling proteins are predicted to be membrane residents.…”

mentioning

confidence: 99%

“…Vps32 binds membranes by itself and through its interacting partners ESCRT-II (49) and ESCRT-III Vps20 (3,28). As Rim20p-containing endosomes segregate spatially from multivesicular body pathway endosomes (6), the prevailing model assumes that the pH signaling pathway hijacks multivesicular body pathway sorting components for its PacC/Rim101p processing purposes (6,16). Although subcellular localization of PalB/Rim13p, the likely signaling protease for PacC and the sole protease for Rim101p activation, has not yet been reported, this calpain-like signaling protease is included with the endosomal membrane module, as yeast Rim13p is a two-hybrid interactor of Vps32 (23), and PalB can potentially be recruited to ESCRT-III through its MIT interacting domain (43).…”

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confidence: 99%

Establishment of the Ambient pH Signaling Complex in Aspergillus nidulans : PalI Assists Plasma Membrane Localization of PalH

et al. 2007

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The Aspergillus nidulans ambient pH signaling pathway involves two transmembrane domain (TMD)-containing proteins, PalH and PalI. We provide in silico and mutational evidence suggesting that PalI is a three TMD (3-TMD) protein with an N-terminal signal peptide, and we show that PalI localizes to the plasma membrane. PalI is not essential for the proteolytic conversion of the PacC translation product into the processed 27-kDa form, but its absence markedly reduces the accumulation of the 53-kDa intermediate after cells are shifted to an alkaline pH. PalI and its homologues contain a predicted luminal, conserved Gly-Cyscontaining motif that distantly resembles a Gly-rich dimerization domain. The Gly44Arg and Gly47Asp substitutions within this motif lead to loss of function. The Gly47Asp substitution prevents plasma membrane localization of PalI-green fluorescent protein (GFP) and leads to its missorting into the multivesicular body pathway. Overexpression of the likely ambient alkaline pH receptor, the 7-TMD protein PalH, partially suppresses the null palI32 mutation. Although some PalH-GFP localizes to the plasma membrane, it predominates in internal membranes. However, the coexpression of PalI to stoichiometrically similar levels results in the strong predominance of PalH-GFP in the plasma membrane. Thus, one role for PalI, but possibly not the only role, is to assist with plasma membrane localization of PalH. These data, considered along with previous reports for both Saccharomyces cerevisiae and A. nidulans, strongly support the prevailing model of pH signaling involving two spatially segregated complexes: a plasma membrane complex containing PalH, PalI, and the arrestin-like protein PalF and an endosomal membrane complex containing PalA and PalB, to which PacC is recruited for its proteolytic activation.

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PalC, One of Two Bro1 Domain Proteins in the Fungal pH Signalling Pathway, Localizes to Cortical Structures and Binds Vps32

Cited by 67 publications

References 72 publications

ESCRT-III-Associated Protein ALIX Mediates High-Affinity Phosphate Transporter Trafficking to Maintain Phosphate Homeostasis in Arabidopsis

ESCRT-III-Associated Protein ALIX Mediates High-Affinity Phosphate Transporter Trafficking to Maintain Phosphate Homeostasis in Arabidopsis

Mutational Analysis of Candida albicans SNF7 Reveals Genetically Separable Rim101 and ESCRT Functions and Demonstrates Divergence in bro1-Domain Protein Interactions

Establishment of the Ambient pH Signaling Complex in Aspergillus nidulans : PalI Assists Plasma Membrane Localization of PalH

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