TY - JOUR
T1 - Initial characterization of the nascent polypeptide-associated complex in yeast
AU - Reimann, Barbara
AU - Bradsher, John
AU - Franke, Jacqueline
AU - Hartmann, Enno
AU - Wiedmann, Martin
AU - Prehn, Siegfried
AU - Wiedmann, Brigitte
PY - 1999/3/30
Y1 - 1999/3/30
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0033616846&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1097-0061(19990330)15:5<397::AID-YEA384>3.0.CO;2-U
DO - 10.1002/(SICI)1097-0061(19990330)15:5<397::AID-YEA384>3.0.CO;2-U
M3 - Journal articles
C2 - 10219998
AN - SCOPUS:0033616846
SN - 0749-503X
VL - 15
SP - 397
EP - 407
JO - Yeast
JF - Yeast
IS - 5
ER -