Evidence for retro-translocation of pokeweed antiviral protein from endoplasmic reticulum into cytosol and separation of its activity on ribosomes from its activity on capped RNA.
AuthorsParikh BA, Baykal U, Di R, Tumer NE
JournalBiochemistry
PubMed ID15709760
'Pokeweed antiviral protein (PAP) is a single-chain ribosome inactivating protein (RIP) that binds to ribosomes and depurinates the highly conserved alpha-sarcin/ricin loop (SRL) of the large subunit rRNA. Catalytic depurination of a specific adenine has been proposed to result in translation arrest and cytotoxicity. Here, we show that both precursor ... More
Humoral immune response to fibrillar beta-amyloid peptide.
'The beta-amyloid peptide (Abeta) is a normal product of the proteolytic processing of its precursor (beta-APP). Normally, it elicits a very low humoral immune response; however, the aggregation of monomeric Abeta to form fibrillar Abeta amyloid creates a neo-epitope, to which antibodies are generated. Rabbits were injected with fibrillar human ... More
The dynamin-related GTPase, Dnm1p, controls mitochondrial morphology in yeast.
AuthorsOtsuga D, Keegan BR, Brisch E, Thatcher JW, Hermann GJ, Bleazard W, Shaw JM
JournalJ Cell Biol
PubMed ID9786946
'The Saccharomyces cerevisiae Dnm1 protein is structurally related to dynamin, a GTPase required for membrane scission during endocytosis. Here we show that Dnm1p is essential for the maintenance of mitochondrial morphology. Disruption of the DNM1 gene causes the wild-type network of tubular mitochondrial membranes to collapse to one side of ... More
Grd19/Snx3p functions as a cargo-specific adapter for retromer-dependent endocytic recycling.
AuthorsStrochlic TI, Setty TG, Sitaram A, Burd CG
JournalJ Cell Biol
PubMed ID17420293
'Amajor function of the endocytic system is the sorting of cargo to various organelles. Endocytic sorting of the yeast reductive iron transporter, which is composed of the Fet3 and Ftr1 proteins, is regulated by available iron. When iron is provided to iron-starved cells, Fet3p-Ftr1p is targeted to the lysosome-like vacuole ... More
Mutational analysis of the mitochondrial copper metallochaperone Cox17.
AuthorsHeaton D, Nittis T, Srinivasan C, Winge DR
JournalJ Biol Chem
PubMed ID10970896
'The copper metallochaperone Cox17 is proposed to shuttle Cu(I) ions to the mitochondrion for the assembly of cytochrome c oxidase. The Cu(I) ions are liganded by cysteinyl thiolates. Mutational analysis on the yeast Cox17 reveals three of the seven cysteinyl residues to be critical for Cox17 function, and these three ... More
The intramitochondrial dynamin-related GTPase, Mgm1p, is a component of a protein complex that mediates mitochondrial fusion.
AuthorsWong ED, Wagner JA, Scott SV, Okreglak V, Holewinske TJ, Cassidy-Stone A, Nunnari J
JournalJ Cell Biol
PubMed ID12566426
'A balance between fission and fusion events determines the morphology of mitochondria. In yeast, mitochondrial fission is regulated by the outer membrane-associated dynamin-related GTPase, Dnm1p. Mitochondrial fusion requires two integral outer membrane components, Fzo1p and Ugo1p. Interestingly, mutations in a second mitochondrial-associated dynamin-related GTPase, Mgm1p, produce similar phenotypes to fzo1 ... More
A novel nuclear import pathway for the transcription factor TFIIS.
AuthorsAlbertini M, Pemberton LF, Rosenblum JS, Blobel G
JournalJ Cell Biol
PubMed ID9852143
'We have identified a novel pathway for protein import into the nucleus. We have shown that the previously identified but uncharacterized yeast protein Nmd5p functions as a karyopherin. It was therefore designated Kap119p (karyopherin with Mr of 119 kD). We localized Kap119p to both the nucleus and the cytoplasm. We ... More
Yeast mitochondrial protein, Nfs1p, coordinately regulates iron-sulfur cluster proteins, cellular iron uptake, and iron distribution.
AuthorsLi J, Kogan M, Knight SA, Pain D, Dancis A
JournalJ Biol Chem
PubMed ID10551871
'Nfs1p is the yeast homolog of the bacterial proteins NifS and IscS, enzymes that release sulfur from cysteine for iron-sulfur cluster assembly. Here we show that the yeast mitochondrial protein Nfs1p regulates cellular and mitochondrial iron homeostasis. A strain of Saccharomyces cerevisiae, MA14, with a missense NFS1 allele (I191S) was ... More
Zinc binding to a regulatory zinc-sensing domain monitored in vivo by using FRET.
AuthorsQiao W, Mooney M, Bird AJ, Winge DR, Eide DJ
JournalProc Natl Acad Sci U S A
PubMed ID16720702
'We have generated probes of metal binding to zinc fingers (ZFs) that provide tools to study zinc trafficking in vivo. In this study, we used these probes to examine zinc binding by the Zap1 transcription factor of Saccharomyces cerevisiae. Zap1 contains two zinc-regulated activation domains (ADs), AD1 and AD2. AD2 ... More
Detection of lipopolysaccharides blotted to polyvinylidene difluoride membranes.
AuthorsStein MA, McAllister SA, Johnston KH, Diedrich DL
JournalAnal Biochem
PubMed ID2221377
Bacterial lipopolysaccharide (LPS) blotted to polyvinylidene difluoride (PVDF) membranes was detected by a technique adapted from current methodologies used to detect glycoproteins. PVDF-bound LPS was coupled to a hapten and localized on the membrane by Western blotting with an antibody-alkaline phosphatase conjugate specific for the hapten. Immobilon blots could be ... More
Splicing before import - an intein in a mitochondrially targeted preprotein folds and is catalytically active in the cytoplasm in vivo.
AuthorsWilliams LR, Ellis SR, Hopper AK, Davis EO, Martin NC
JournalFEBS Lett
PubMed ID10913632
Nuclear-encoded mitochondrial proteins are cytoplasmically synthesized and imported into the organelle. The intein-containing RecA protein of Mycobacterium tuberculosis, with or without the CoxIVp mitochondrial targeting signal (MTS), was used to determine where a protein targeted to mitochondria folds and becomes catalytically active. Analysis of fractions from Saccharomyces cerevisiae cells expressing ... More
Vta1p and Vps46p regulate the membrane association and ATPase activity of Vps4p at the yeast multivesicular body.
Previous two-hybrid analysis of the 17 soluble class E Vps yeast proteins revealed that Vps46p/Did2p interacts with Vta1p and the AAA (ATPase associated with a variety of cellular activities) ATPase Vps4p. Here we report that the binding of Vps46p to Vps4p and Vta1p is direct and not mediated by additional ... More
Aut7p, a soluble autophagic factor, participates in multiple membrane trafficking processes.
AuthorsLegesse-Miller A, Sagiv Y, Glozman R, Elazar Z
JournalJ Biol Chem
PubMed ID10837468
Aut7p, a protein recently implicated in autophagic events in the yeast Saccharomyces cerevisiae, exhibits significant homology to a mammalian protein, p16, herein termed GATE-16 (Golgi-associated ATPase Enhancer of 16 kDa), a novel intra-Golgi transport factor. Here we provide evidence for the involvement of Aut7p in different membrane trafficking processes. Aut7p ... More
Proteasome-mediated protein processing by bidirectional degradation initiated from an internal site.
AuthorsPiwko W, Jentsch S
JournalNat Struct Mol Biol
PubMed ID16845392
The proteasome is a barrel-shaped protease that conceals its active sites within its central cavity. Proteasomes usually completely degrade substrates into small peptides, but in some cases, degradation yields biologically active protein fragments. Some transcription factors are generated from precursors by this activity, but the mechanism of proteasomal protein processing ... More
The characterization and role of zinc binding in yeast Cox4.
AuthorsCoyne HJ, Ciofi-Baffoni S, Banci L, Bertini I, Zhang L, George GN, Winge DR
JournalJ Biol Chem
PubMed ID17215247
Yeast Cox4 is a zinc binding subunit of cytochrome c oxidase. Cox4 is the only cofactor-containing subunit that is not directly part of the catalytic core of the enzyme located in the mitochondrial inner membrane. The Zn(II) site is shown to be distinct from the bovine ortholog, as it results ... More
Erf4p and Erf2p form an endoplasmic reticulum-associated complex involved in the plasma membrane localization of yeast Ras proteins.
Ras oncogene proteins are plasma membrane-associated signal transducers that are found in all eukaryotes. Posttranslational addition of lipid to a carboxyl-terminal CaaX box (where "C" represents a cysteine, "a" is generally an aliphatic residue, and X can be any amino acid) is required to target Ras proteins to the cytosolic ... More
J-domain protein, Jac1p, of yeast mitochondria required for iron homeostasis and activity of Fe-S cluster proteins.
AuthorsKim R, Saxena S, Gordon DM, Pain D, Dancis A
JournalJ Biol Chem
PubMed ID11278728
J-proteins are molecular chaperones with a characteristic domain predicted to mediate interaction with Hsp70 proteins. We have previously isolated yeast mutants of the mitochondrial Hsp70, Ssq1p, in a genetic screen for mutants with altered iron homeostasis. Here we describe the isolation of mutants of the J-domain protein, Jac1p, using the ... More
The yeast Hsp110 family member, Sse1, is an Hsp90 cochaperone.
AuthorsLiu XD, Morano KA, Thiele DJ
JournalJ Biol Chem
PubMed ID10480867
In eukaryotes, production of the diverse repertoire of molecular chaperones during normal growth and in response to stress is governed by the heat shock transcription factor HSF. The HSC82 and HSP82 genes, encoding isoforms of the yeast Hsp90 molecular chaperone, were recently identified as targets of the HSF carboxyl-terminal activation ... More
The critical mutagenic translesion DNA polymerase Rev1 is highly expressed during G(2)/M phase rather than S phase.
AuthorsWaters LS, Walker GC
JournalProc Natl Acad Sci U S A
PubMed ID16751278
The Rev1 protein lies at the root of mutagenesis in eukaryotes. Together with DNA polymerase zeta (Rev3/7), Rev1 function is required for the active introduction of the majority of mutations into the genomes of eukaryotes from yeast to humans. Rev1 and polymerase zeta are error-prone translesion DNA polymerases, but Rev1's ... More
Mdv1p is a WD repeat protein that interacts with the dynamin-related GTPase, Dnm1p, to trigger mitochondrial division.
AuthorsTieu Q, Nunnari J
JournalJ Cell Biol
PubMed ID11038182
Mitochondrial fission is mediated by the dynamin-related GTPase, Dnm1p, which assembles on the mitochondrial outer membrane into punctate structures associated with sites of membrane constriction and fission. We have identified additional nuclear genes required for mitochondrial fission, termed MDV (for mitochondrial division). MDV1 encodes a predicted soluble protein, containing a ... More
Molecular characterization of FMN1, the structural gene for the monofunctional flavokinase of Saccharomyces cerevisiae.
AuthorsSantos MA, Jimenez A, Revuelta JL
JournalJ Biol Chem
PubMed ID10887197
Flavokinase catalyzes the transfer of the gamma-phosphoryl group of ATP to riboflavin to form the flavocoenzyme FMN. Consistent patterns of sequence similarities have identified the open reading frame of unknown function YDR236c as a candidate to encode flavokinase in Saccharomyces cerevisiae. In order to determine whether the product of this ... More