Physiological effects of unassembled chaperonin Cct subunits in the yeast Saccharomyces cerevisiae

Kabir, M. A., Kaminska, J., Segel, G. B., Bethlendy, G., Lin, P., Della Seta, F., Blegen, C., Swiderek, K. M., Zoladek, T., Arndt, K. T., Sherman, F. (February 2005) Physiological effects of unassembled chaperonin Cct subunits in the yeast Saccharomyces cerevisiae. Yeast, 22 (3). pp. 219-239. ISSN 0749-503X

DOI: 10.1002/yea.1210


Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed of a stoichiometric array of eight different subunits, which are denoted Cct1p-Cct8p. Overexpression of a single CCT gene in Saccharomyces cerevisiae causes an increase of the corresponding Cct subunit, but not of the Cct complex. Nevertheless, overexpression of certain Cct subunits, especially CCT6, suppresses a wide range of abnormal phenotypes, including those caused by the diverse types of conditional mutations tor2-21, lst8-2 and rsp5-9 and those caused by the concomitant overexpression of Sit4p and Sap155p. The examination of 73 altered forms of Cct6p revealed that the cct6-24 mutation, containing GDGTT --> AAAAA replacements of the conserved ATP-binding motif, was unable to suppress any of these traits, although the cct6-24 allele was completely functional for growth. These results provide evidence for functional differences among Cct subunits and for physiological properties of unassembled subunits. We suggest that the suppression is due to the competition of specific Cct subunits for activities that normally modify various cellular components. Furthermore, we also suggest that the Cct subunits can act as suppressors only in certain states, such as when associated with ATP. Copyright (C) 2005 John Wiley Sons, Ltd.

Item Type: Paper
Uncontrolled Keywords: chaperonins Cct TOR2 LST8 RSP5 SIT4 SAP155 ubiquitin protein ligase amino acid permease TOR signaling pathway cytosolic chaperonin actin cytoskeleton cell growth eukaryotic chaperonin functional characterization translation initiation tryptophan permeation
Subjects: bioinformatics > genomics and proteomics > annotation > gene expression profiling annotation
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > chaperonins
CSHL Authors:
Communities: CSHL labs
Depositing User: CSHL Librarian
Date: February 2005
Date Deposited: 10 Jan 2012 19:03
Last Modified: 07 May 2018 15:46
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