Reference: Deloche O, et al. (1997) Structure-function analyses of the Ssc1p, Mdj1p, and Mge1p Saccharomyces cerevisiae mitochondrial proteins in Escherichia coli. J Bacteriol 179(19):6066-75

Reference Help

Abstract

The DnaK, DnaJ, and GrpE proteins of Escherichia coli have been universally conserved across the biological kingdoms and work together to constitute a highly efficient molecular chaperone machine. We have examined the extent of functional conservation of Saccharomyces cerevisiae Ssc1p, Mdj1p, and Mge1p by analyzing their ability to substitute for their corresponding E. coli homologs in vivo. We found that the expression of yeast Mge1p, the GrpE homolog, allowed for the deletion of the otherwise essential grpE gene of E. coli, albeit only up to 40 degrees C. The inability of Mge1p to substitute for GrpE at very high temperatures is consistent with our previous finding that it specifically failed to stimulate DnaK's ATPase at such extreme conditions. In contrast to Mge1p, overexpression of Mdj1p, the DnaJ homolog, was lethal in E. coli. This toxicity was specifically relieved by mutations which affected the putative zinc binding region of Mdj1p. Overexpression of a truncated version of Mdj1p, containing the J- and Gly/Phe-rich domains, partially substituted for DnaJ function at high temperature. A chimeric protein, consisting of the J domain of Mdj1p coupled to the rest of DnaJ, acted as a super-DnaJ protein, functioning even more efficiently than wild-type DnaJ. In contrast to the results with Mge1p and Mdj1p, both the expression and function of Ssc1p, the DnaK homolog, were severely compromised in E. coli. We were unable to demonstrate any functional complementation by Ssc1p, even when coexpressed with its Mdj1p cochaperone in E. coli.

Reference Type
Journal Article | Research Support, Non-U.S. Gov't
Authors
Deloche O, Kelley WL, Georgopoulos C
Primary Lit For
Additional Lit For
Review For

Interaction Annotations

Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Type Assay Annotation Action Modification Phenotype Source Reference

Gene Ontology Annotations

Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Gene Gene Ontology Term Qualifier Aspect Method Evidence Source Assigned On Annotation Extension Reference

Phenotype Annotations

Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.

Gene Phenotype Experiment Type Mutant Information Strain Background Chemical Details Reference

Regulation Annotations

Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.

Regulator Target Experiment Assay Construct Conditions Strain Background Reference