Submitted to: International Congress of Stress
Publication Type: Abstract Only
Publication Acceptance Date: 7/5/1997
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: Molecular chaperones are proteins that bind to and stabilize an otherwise unstable polypeptide conformation, and through a controlled cycle of binding and release facilitate the correct fate. The archetypal Hsp70 chaperone machine consists of the central chaperone plus two cohort proteins. In E. coli these three components are the products of the dnaK, dnaJ, and grpE genes. DnaJ interacts with the DnaK-GrpE-target polypeptide ternary complex and stimulates the rate of ATP hydrolysis by DnaK. There is also evidence that DnaJ can function independently as a chaperone. The genome of the model plant Arabidopsis thaliana contains at least 10 genes encoding DnaJ homologues. To date, we have isolated cDNA clones for six Arabidopsis DnaJ homologues, AtJ1-6. AtJ1 is localized within the mitochondrial matrix. AtJ2-5 are most like the yeast YdJ1 proteins and are localized within the cytoplasm or in association with the outer surface of organellar membranes. AtJ6 is more similar to the human DnaJ homologue, HdJ1, and is likely cytoplasmic. The ability of recombinant AtJ proteins to activate the ATPase function of both DnaK and plant Hsp70 proteins will be compared.