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Title
'In Silico' Identification of Carboxylate Clamp Type Tetratricopeptide Repeat Proteins in 'Arabidopsis' and Rice As Putative Co-Chaperones of Hsp90/Hsp70
Fields of Research (FoR) 2008:
Author(s)
Publication Date
2010
Socio-Economic Objective (SEO) 2008
Open Access
Yes
Abstract
The essential eukaryotic molecular chaperone Hsp90 operates with the help of different co-chaperones, which regulate its ATPase activity and serve as adaptors to recruit client proteins and other molecular chaperones, such as Hsp70, to the Hsp90 complex. Several Hsp90 and Hsp70 co-chaperones contain the tetratricopeptide repeat (TPR) domain, which interacts with the highly conserved EEVD motif at the C-terminal ends of Hsp90 and Hsp70. The acidic side chains in EEVD interact with a subset of basic residues in the TPR binding pocket called a 'carboxylate clamp'. Since the carboxylate clamp residues are conserved in the TPR domains of known Hsp90/Hsp70 co-chaperones, we carried out an in silico search for TPR proteins in 'Arabidopsis' and rice comprising of at least one three-motif TPR domain with conserved amino acid residues required for Hsp90/Hsp70 binding. This approach identified in Arabidopsis a total of 36 carboxylate clamp (CC)-TPR proteins, including 24 novel proteins, with potential to interact with Hsp90/Hsp70. The newly identified CC-TPR proteins in 'Arabidopsis' and rice contain additional protein domains such as ankyrin, SET, octicosapeptide/Phox/Bem1p (Phox/PB1), DnaJ-like, thioredoxin, FBD and F-box, and protein kinase and U-box, indicating varied functions for these proteins. To provide proof-of-concept of the newly identified CC-TPR proteins for interaction with Hsp90, we demonstrated interaction of AtTPR1 and AtTPR2 with AtHsp90 in yeast two-hybrid and 'in vitro' pull down assays. These findings indicate that the 'in silico' approach used here successfully identified in a genome-wide context CC-TPR proteins with potential to interact with Hsp90/Hsp70, and further suggest that the Hsp90/Hsp70 system relies on TPR co-chaperones more than it was previously realized.
Publication Type
Journal Article
Source of Publication
PLoS One, 5(9), p. 1-18
Publisher
Public Library of Science
Place of Publication
United States of America
ISSN
1932-6203
Peer Reviewed
Yes
HERDC Category Description
Peer Reviewed
Yes
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