Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Functional studies of hephaestin in yeast: evidence for multicopper oxidase activity in the endocytic pathway.

ABSTRACT: Hephaestin is a mammalian gene that encodes a predicted multicopper oxidase required for intestinal iron export. To examine if hephaestin can act as a ferroxidase, we studied yeast strains transformed with plasmids containing both a full-length hephaestin and a hephaestin lacking a transmembrane domain. Yeast with a deletion in FET3, which encodes a cell-surface multicopper oxidase, cannot grow on low-iron media. Expression of full-length hephaestin could complement the low-iron growth phenotype of a Delta fet3 strain. Complementation of Delta fet3 cells by hephaestin required genes that encode proteins necessary for the copper loading of Fet3p, including CCC2 and GEF1. Expression of hephaestin in Delta fet3 cells led to an increase in both iron transport and oxidase activity. These results demonstrate that hephaestin is a copper-dependent protein. In contrast with Fet3p, which is found on the cell surface, hephaestin was co-localized with Pep12p-containing vesicles. Inhibition of endocytosis or deletion of both the vacuolar iron transporters ( SMF3 and FET5 / FTH1 ) prevented hephaestin from complementing the low-iron growth phenotype of Delta fet3 cells, suggesting that hephaestin is functioning within the endocytic apparatus.

SUBMITTER: Li L

PROVIDER: S-EPMC1223732 | biostudies-other | 2003 Nov

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Rab GTPases and tethering in the yeast endocytic pathway.

Project description:Within eukaryotic cells, Rab GTPases control the maturation of early to late endosomes and their subsequent fusion with the vacuole. Within this ExtraView, we will focus on our recent findings regarding the activation of the Rab7 homolog Ypt7 in yeast and its interplay with the two multisubunit tethering complexes CORVET and HOPS.

| S-EPMC3136951 | biostudies-literature

Functional links between A? toxicity, endocytic trafficking, and Alzheimer's disease risk factors in yeast.

Project description:A? (beta-amyloid peptide) is an important contributor to Alzheimer's disease (AD). We modeled A? toxicity in yeast by directing the peptide to the secretory pathway. A genome-wide screen for toxicity modifiers identified the yeast homolog of phosphatidylinositol binding clathrin assembly protein (PICALM) and other endocytic factors connected to AD whose relationship to A? was previously unknown. The factors identified in yeast modified A? toxicity in glutamatergic neurons of Caenorhabditis elegans and in primary rat cortical neurons. In yeast, A? impaired the endocytic trafficking of a plasma membrane receptor, which was ameliorated by endocytic pathway factors identified in the yeast screen. Thus, links between A?, endocytosis, and human AD risk factors can be ascertained with yeast as a model system.

| S-EPMC3281757 | biostudies-literature

Selection and stabilization of endocytic sites by Ede1, a yeast functional homologue of human Eps15.

Project description:During clathrin-mediated endocytosis (CME), endocytic-site maturation can be divided into two stages corresponding to the arrival of the early and late proteins at the plasma membrane. The early proteins are required to capture cargo and position the late machinery, which includes proteins involved in actin assembly and membrane scission. However, the mechanism by which early-arriving proteins select and stabilize endocytic sites is not known. Ede1, one of the earliest proteins recruited to endocytic sites, facilitates site initiation and stabilization. Deletion of EDE1 results in fewer CME initiations and defects in the timing of vesicle maturation. Here we made truncation mutants of Ede1 to better understand how different domains contribute to its recruitment to CME sites, site selection, and site maturation. We found that the minimal domains required for efficient Ede1 localization at CME sites are the third EH domain, the proline-rich region, and the coiled-coil region. We also found that many strains expressing ede1 truncations could support a normal rate of site initiation but still had defects in site-maturation timing, indicating separation of Ede1 functions. When expressed in yeast, human Eps15 localized to the plasma membrane, where it recruited late-phase CME proteins and supported productive endocytosis, identifying it as an Ede1 functional homologue.

| S-EPMC5328616 | biostudies-literature

Functional studies of the Yeast Mediator Tail Module Subunits

2013-06-07 | GSE47712 | GEO

The yeast endocytic protein Epsin 2 functions in a cell-division signaling pathway.

Project description:The epsins are a family of adaptors involved in recruiting other endocytic proteins, binding of ubiquitylated cargo and induction of membrane curvature. These molecules bear a characteristic epsin N-terminal homology (ENTH) domain and multiple peptide motifs that mediate protein-protein interactions. We have previously demonstrated that the ENTH domain of epsin is involved in Cdc42 signaling regulation. Here, we present evidence that yeast epsin 2 (Ent2) plays a signaling role during cell division. We observed that overexpression of the ENTH domain of Ent2 (ENTH2), but not Ent1, promoted the formation of chains of cells and aberrant septa. This dominant-negative effect resulted from ENTH2-mediated interference with septin assembly pathways. We mapped the ENTH2 determinants responsible for induction of the phenotype and found them to be important for efficient binding to the septin regulatory protein, Bem3. Supporting a physiological role for epsin 2 in cell division, the protein localized to sites of polarized growth and cytokinesis and rescued a defect in cell division induced by Bem3 misregulation. Collectively, our findings provide a potential molecular mechanism linking endocytosis (via epsin 2) with signaling pathways regulating cell division.

| S-EPMC2704880 | biostudies-other

Endocytic recycling in yeast is regulated by putative phospholipid translocases and the Ypt31p/32p-Rcy1p pathway.

Project description:Phospholipid translocases (PLTs) have been implicated in the generation of phospholipid asymmetry in membrane bilayers. In budding yeast, putative PLTs are encoded by the DRS2 gene family of type 4 P-type ATPases. The homologous proteins Cdc50p, Lem3p, and Crf1p are potential noncatalytic subunits of Drs2p, Dnf1p and Dnf2p, and Dnf3p, respectively; these putative heteromeric PLTs share an essential function for cell growth. We constructed temperature-sensitive mutants of CDC50 in the lem3Delta crf1Delta background (cdc50-ts mutants). Screening for multicopy suppressors of cdc50-ts identified YPT31/32, two genes that encode Rab family small GTPases that are involved in both the exocytic and endocytic recycling pathways. The cdc50-ts mutants did not exhibit major defects in the exocytic pathways, but they did exhibit those in endocytic recycling; large membranous structures containing the vesicle-soluble N-ethylmaleimide-sensitive factor attachment protein receptor Snc1p intracellularly accumulated in these mutants. Genetic results suggested that the YPT31/32 effector RCY1 and CDC50 function in the same signaling pathway, and simultaneous overexpression of CDC50, DRS2, and GFP-SNC1 restored growth as well as the plasma membrane localization of GFP-Snc1p in the rcy1Delta mutant. In addition, Rcy1p coimmunoprecipitated with Cdc50p-Drs2p. We propose that the Ypt31p/32p-Rcy1p pathway regulates putative phospholipid translocases to promote formation of vesicles destined for the trans-Golgi network from early endosomes.

| S-EPMC1751321 | biostudies-literature

An Abp1-dependent route of endocytosis functions when the classical endocytic pathway in yeast is inhibited.

Project description:Clathrin-mediated endocytosis (CME) is a well characterized pathway in both yeast and mammalian cells. An increasing number of alternative endocytic pathways have now been described in mammalian cells that can be both clathrin, actin, and Arf6- dependent or independent. In yeast, a single clathrin-mediated pathway has been characterized in detail. However, disruption of this pathway in many mutant strains indicates that other uptake pathways might exist, at least for bulk lipid and fluid internalization. Using a combination of genetics and live cell imaging, here we show evidence for a novel endocytic pathway in S. cerevisiae that does not involve several of the proteins previously shown to be associated with the 'classic' pathway of endocytosis. This alternative pathway functions in the presence of low levels of the actin-disrupting drug latrunculin-A which inhibits movement of the proteins Sla1, Sla2, and Sac6, and is independent of dynamin function. We reveal that in the absence of the 'classic' pathway, the actin binding protein Abp1 is now essential for bulk endocytosis. This novel pathway appears to be distinct from another described alternative endocytic route in S. cerevisiae as it involves at least some proteins known to be associated with cortical actin patches rather than being mediated at formin-dependent endocytic sites. These data indicate that cells have the capacity to use overlapping sets of components to facilitate endocytosis under a range of conditions.

| S-EPMC4114835 | biostudies-literature

Dynamic studies of scaffold-dependent mating pathway in yeast.

Project description:The mating pathway in Saccharomyces cerevisiae is one of the best understood signal transduction pathways in eukaryotes. It transmits the mating signal from plasma membrane into the nucleus through the G-protein coupled receptor and the mitogen-activated protein kinase (MAPK) cascade. According to current understanding of the mating pathway, we construct a system of ordinary differential equations to describe the process. Our model is consistent with a wide range of experiments, indicating that it captures some main characteristics of the signal transduction along the pathway. Investigation with the model reveals that the shuttling of the scaffold protein and the dephosphorylation of kinases involved in the MAPK cascade cooperate to regulate the response upon pheromone induction and to help preserve the fidelity of the mating signaling. We explored factors affecting the dose-response curves of this pathway and found that both negative feedback and concentrations of the proteins involved in the MAPK cascade play crucial roles. Contrary to some other MAPK systems where signaling sensitivity is being amplified successively along the cascade, here the mating signal is transmitted through the cascade in an almost linear fashion.

| S-EPMC1635675 | biostudies-literature

Functional studies of the Yeast Mediator Tail Module Subunits

Project description:The yeast Mediator complex can be divided into three modules, designated Head, Middle and Tail. Tail comprises the Med2, Med3, Med5, Med15 and Med16 protein subunits, which are all encoded by genes that are individually non-essential for viability. In cells lacking Med16, Tail is displaced from Head and Middle. However, inactivation of MED5/MED15 and MED15/MED16 are synthetically lethal, indicating that Tail performs essential functions as a separate complex even when it is not bound to Middle and Head. We have used the N-Degron method to create temperature sensitive (ts) mutants in the Mediator tail subunits Med5, Med15 and Med16 to study the immediate effects on global gene expression when each subunit is individually inactivated, and when MED5/15 or MED15/16 are inactivated together. All Degron constructs were expressed from their normal chromosomal location under the control of their respective endogenous promoters. We isolated RNA from each strain as early as 45 minutes after changing from the permissive to the restrictive growth conditions to minimize possible secondary effects on gene expression that are not directly caused by the Degron construct(s).

2013-06-07 | E-GEOD-47712 | biostudies-arrayexpress

Evidence for a clathrin-independent endocytic pathway for APP internalization in the neuronal somatodendritic compartment.

Project description:Amyloid precursor protein (APP) internalization via clathrin-/dynamin-mediated endocytosis (CME) mediated by its YENPTY motif into endosomes containing β-secretase is proposed to be critical for amyloid-beta (Aβ) production. Here, we show that somatodendritic APP internalization in primary rodent neurons is not blocked by inhibiting dynamin or mutating the YENPTY motif, in contrast to non-neuronal cell lines. These phenomena, confirmed in induced human neurons under dynamin inhibition, occur during basal conditions and chemical long-term-depression stimulus, pointing to a clathrin-independent internalization pathway for somatodendritic APP. Mutating the YENPTY motif does not alter APP recycling, degradation, or endolysosomal colocalization. However, both dynamin inhibition and the YENPTY mutant significantly decrease secreted Aβ in neurons, suggesting that internalized somatodendritic APP may not constitute a major source of Aβ. Interestingly, like APP, somatodendritic low-density lipoprotein receptor (LDLR) internalization does not require its CME motif. These results highlight intriguing differences in neuronal internalization pathways and refine our understanding of Aβ production and secretion.

| S-EPMC10449584 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data