| Autor: |
Lee U; Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, Arizona 85721, USA., Wie C, Escobar M, Williams B, Hong SW, Vierling E |
| Jazyk: |
angličtina |
| Zdroj: |
The Plant cell [Plant Cell] 2005 Feb; Vol. 17 (2), pp. 559-71. Date of Electronic Publication: 2005 Jan 19. |
| DOI: |
10.1105/tpc.104.027540 |
| Abstrakt: |
We have defined amino acids important for function of the Arabidopsis thaliana Hsp100/ClpB chaperone (AtHsp101) in acquired thermotolerance by isolating recessive, loss-of-function mutations and a novel semidominant, gain-of-function allele [hot1-4 (A499T)]. The hot1-4 allele is unusual in that it not only fails to develop thermotolerance to 45 degrees C after acclimation at 38 degrees C, but also is sensitive to 38 degrees C, which is a permissive temperature for wild-type and loss-of-function mutants. hot1-4 lies between nucleotide binding domain 1 (NBD1) and NBD2 in a coiled-coil domain that is characteristic of the Hsp100/ClpB proteins. We then isolated two classes of intragenic suppressor mutations of hot1-4: loss-of-function mutations (Class 1) that eliminated the 38 degrees C sensitivity, but did not restore thermotolerance function to hot1-4, and Class 2 suppressors that restored acquired thermotolerance function to hot1-4. Location of the hot1-4 Class 2 suppressors supports a functional link between the coiled-coil domain and both NBD1 and the axial channel of the Hsp100/ClpB hexamer. In addition, the strongest Class 2 suppressors restored solubility of aggregated small heat shock proteins (sHsps) after heat stress, revealing genetic interaction of the Hsp100/ClpB and sHsp chaperone systems. These results also demonstrate that quantitative phenotypes can be used for in vivo genetic dissection of protein mechanism in Arabidopsis. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
|
