Initial characterization of the nascent polypeptide-associated complex in yeast Journal Article

Authors: Reimann, B.; Bradsher, J.; Franke, J.; Hartmann, E.; Wiedmann, M.; Prehn, S.; Wiedmann, B.
Article Title: Initial characterization of the nascent polypeptide-associated complex in yeast
Abstract: The three subunits of the nascent polypeptide associated complex (α, β1, β3,) in Saccharomyces cerevisiae are encoded by three genes (EGD2, EGD1, BTT1). We found the complex bound to ribosomes via the β-subunits in a salt-sensitive manner, in close proximity to nascent polypeptides. Estimation of the molecular weight of the complex of wild-type cells and cells lacking one or two subunits revealed that the composition of the complex is variable and that as yet unknown proteins might be included. Regardless of the variability, a certain balance of the subunits has to be maintained: the deletion of one subunit causes downregulation of the remaining subunits at physiological growth temperature. Cells lacking both β-subunits are unable to grow at 37°C, most likely due to a toxic effect of the α-subunit. Based on in vitro experiments, it has been proposed that the function of mammalian nascent-polypeptide associated complexes (NAC) is to prevent inappropriate targeting of non-secretory nascent polypeptides. In vivo, however, the lack of NAC does not cause secretion of signal-less invertase in yeast. This result and the lack of a drastic phenotype of cells missing one, two or three subunits at optimal conditions (28°C, YPD-medium) suggest either the existence of a substitute for NAC or that cells tolerate or 'repair' the damage caused by the absence of NAC.
Keywords: controlled study; gene deletion; dna-binding proteins; nonhuman; phenotype; mammalia; transcription factors; nuclear proteins; blotting, western; protein processing, post-translational; protein synthesis; saccharomyces cerevisiae; temperature; trans-activators; saccharomyces cerevisiae proteins; protein subunit; molecular weight; fungi; fungus growth; electrophoresis, polyacrylamide gel; ribosomes; polypeptide; fungal proteins; glycoside hydrolases; ribosome; molecular chaperones; nac; precipitin tests; priority journal; article; beta-fructofuranosidase; nascent-polypeptide-associated complex
Journal Title: Yeast
Volume: 15
Issue: 5
ISSN: 0749-503X
Publisher: John Wiley & Sons Ltd.  
Date Published: 1999-03-01
Start Page: 397
End Page: 407
Language: English
DOI: 10.1002/(sici)1097-0061(19990330)15:5<397::aid-yea384>;2-u
PUBMED: 10219998
PROVIDER: scopus
Notes: Article -- Export Date: 16 August 2016 -- Source: Scopus
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