The t complex polypeptide 1 (TCP-1) is associated with the cytoplasmic aspect of Golgi membranes

Willison, Keith R.; Lewis, Victoria; Zuckerman, Kenneth S.; Cordell, Jacqueline; Dean, C; Miller, Karen; Lyon, Mary F.; Marsh, Mark

doi:10.1016/0092-8674(89)90131-1

Cited by 83 publications

(51 citation statements)

References 54 publications

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“…There are previous reports that HSP60s in bacteria and mitochondria, which form group I chaperonins, are membrane associated (33)(34)(35)(36)(37). There are also reports that the HSP60-related TCP1s in eukarya, which form group II chaperonins (known as CCT or TriC), are membrane associated (38)(39)(40)(41). We recently discovered that in human red blood cells TCP1 is predominantly cytoplasmic under normal conditions, but after heat treatment it relocates to the membrane (C. T. Wagner, I. Y. Lu, M. H. Hoffman, W. Q.…”

Section: Discussionmentioning

confidence: 99%

Intracellular localization of a group II chaperonin indicates a membrane-related function

Trent

Kagawa

Paavola

et al. 2003

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

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Chaperonins are protein complexes that are believed to function as part of a protein folding system in the cytoplasm of the cell. We observed, however, that the group II chaperonins known as rosettasomes in the hyperthermophilic archaeon Sulfolobus shibatae, are not cytoplasmic but membrane associated. This association was observed in cultures grown at 60°C and 76°C or heat-shocked at 85°C by using immunofluorescence microscopy and in thick sections of rapidly frozen cells grown at 76°C by using immunogold electron microscopy. We observed that increased abundance of rosettasomes after heat shock correlated with decreased membrane permeability at lethal temperature (92°C). This change in permeability was not seen in cells heat-shocked in the presence of the amino acid analogue azetidine 2-carboxylic acid, indicating functional protein synthesis influences permeability. Azetidine experiments also indicated that observed heat-induced changes in lipid composition in S. shibatae could not account for changes in membrane permeability. Rosettasomes purified from cultures grown at 60°C and 76°C or heat-shocked at 85°C bind to liposomes made from either the bipolar tetraether lipids of Sulfolobus or a variety of artificial lipid mixtures. The presence of rosettasomes did not significantly change the transition temperature of liposomes, as indicated by differential scanning calorimetry, or the proton permeability of liposomes, as indicated by pyranine fluorescence. We propose that these group II chaperonins function as a structural element in the natural membrane based on their intracellular location, the correlation between their functional abundance and membrane permeability, and their potential distribution on the membrane surface.

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Section: Discussionmentioning

confidence: 99%

Intracellular localization of a group II chaperonin indicates a membrane-related function

Trent

Kagawa

Paavola

et al. 2003

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

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“…The endoplasmic reticulum marker anti-ERp60 is raised in rabbit against porcine ERp60 peptide PIIQEEKPKKKKKAQEDL in the C terminus of the protein (32). The Golgi marker 23C rat monoclonal, IgG2c, clone 23c was raised in rats against recombinant mouse TCP-1␣, C-terminal half (33).…”

Section: Antibodiesmentioning

confidence: 99%

Altered Glycosylated PrP Proteins Can Have Different Neuronal Trafficking in Brain but Do Not Acquire Scrapie-like Properties

Cancellotti

Wiseman

Tuzi

et al. 2005

Journal of Biological Chemistry

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N-Linked glycans have been shown to have an important role in the cell biology of a variety of cell surface glycoproteins, including PrP protein. It has been suggested that glycosylation of PrP can influence the susceptibility to transmissible spongiform encephalopathy and determine the characteristics of the many different strains observed in this particular type of disease. To understand the role of carbohydrates in influencing the PrP maturation, stability, and cell biology, we have produced and analyzed gene-targeted murine models expressing differentially glycosylated PrP. Transgenic mice carrying the PrP substitution threonine for asparagine 180 (G1) or threonine for asparagine 196 (G2) or both mutations combined (G3), which eliminate the first, second, and both glycosylation sites, respectively, have been generated by double replacement gene targeting. An in vivo analysis of altered PrP has been carried out in transgenic mouse brains, and our data show that the lack of glycans does not influence PrP maturation and stability. The presence of one chain of sugar is sufficient for the trafficking to the cell membrane, whereas the unglycosylated PrP localization is mainly intracellular. However, this altered cellular localization of PrP does not lead to any overt phenotype in the G3 transgenic mice. Most importantly, we found that, in vivo, unglycosylated PrP does not acquire the characteristics of the aberrant pathogenic form (PrP Sc ), as was previously reported using in vitro models.

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“…The P5 antibody that recognizes the y-subunit of CCT was used for nondenatured samples only (Joly et al, 1994). For immunoprecipitation of CCT from denatured samples, a mixture of a rabbit polyclonal antibody made against a synthetic peptide of mouse TCP-1 and the rat monoclonal antibodies 84a and 91a (Willison et al, 1989, obtained from Stressgen) was used. A rabbit polyclonal antibody to hsp4o was prepared using recombinant human hsp4o as immunogen (Nagata et al, manuscript in preparation).…”

Section: Antibodies and Immunoprecipitation Techniquesmentioning

confidence: 99%

Complexes between nascent polypeptides and their molecular chaperones in the cytosol of mammalian cells.

Eggers

Welch

Hansen

1997

MBoC

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Folding of newly synthesized proteins in vivo is believed to be facilitated by the cooperative interaction of a defined group of proteins known as molecular chaperones.We investigated the direct interaction of chaperones with nascent polypeptides in the cytosol of mammalian cells by multiple methods. A new approach using a polyclonal antibody to puromycin allowed us to tag and capture a population of truncated nascent polypeptides with no bias as to the identity of the bound chaperones. In addition, antibodies that recognize the cytosolic chaperones hsp7O, CCT (TRiC), hsp4O, p48 (Hip), and hsp9O were compared on the basis of their ability to coprecipitate nascent polypeptides, both before and after chemical cross-linking. By all three approaches, hsp7O was found to be the predominant chaperone bound to nascent polypeptides. The interaction between hsp7O and nascent polypeptides is apparently dynamic under physiological conditions but can be stabilized by depletion of ATP or by cross-linking. The cytosolic chaperonin CCT was found to bind primarily to full-length, newly synthesized actin, and tubulin. We demonstrate and caution that nascent polypeptides have a propensity for binding many proteins nonspecifically in cell lysates. Although current models of protein folding in vivo have described additional components in contact with nascent polypeptides, our data indicate that the hsp7O and, perhaps, the hsp9O families are the predominant classes of molecular chaperones that interact with the general population of cytosolic nascent polypeptides.

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The t complex polypeptide 1 (TCP-1) is associated with the cytoplasmic aspect of Golgi membranes

Cited by 83 publications

References 54 publications

Intracellular localization of a group II chaperonin indicates a membrane-related function

Intracellular localization of a group II chaperonin indicates a membrane-related function

Altered Glycosylated PrP Proteins Can Have Different Neuronal Trafficking in Brain but Do Not Acquire Scrapie-like Properties

Complexes between nascent polypeptides and their molecular chaperones in the cytosol of mammalian cells.

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