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. 2001 Jul;6(3):238-46.
doi: 10.1379/1466-1268(2001)006<0238:thfopi>2.0.co;2.

The Hsp90 family of proteins in Arabidopsis thaliana

P Krishna  1 , G Gloor
Affiliations

The Hsp90 family of proteins in Arabidopsis thaliana

P Krishna et al. Cell Stress Chaperones. 2001 Jul.

Abstract

The 90-kDa heat shock protein (Hsp90) is an essential molecular chaperone in eukaryotic cells, with key roles in the folding and activation of proteins involved in signal transduction and control of the cell cycle. A search for Hsp90 sequences in the Arabidopsis thaliana genome revealed that this family includes 7 members. The AtHsp90-1 through AtHsp90-4 proteins constitute the cytoplasmic subfamily, whereas the AtHsp90-5, AtHsp90-6, and AtHsp90-7 proteins are predicted to be within the plastidial, mitochondrial, and endoplasmic reticulum compartments, respectively. The deduced amino acid sequences of each of the cytoplasmic proteins contains the highly conserved C-terminal pentapeptide MEEVD. All of the AtHsp90 sequences include a conserved adenosine triphosphate-binding domain, whereas only the cytoplasmic and endoplasmic reticulum-resident sequences include an adjacent charged linker domain that is common in mammalian and yeast sequences. The occurrence of multiple AtHsp90 proteins in the cytoplasm and of family members in other subcellular compartments suggests a range of specific functions and target polypeptides.

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Figures

Fig 1.
Fig 1.
Molecular phylogeny of the AtHsp90 family of genes. This diagram shows the number of amino acid substitutions per amino acid position that is observed between a given protein and the inferred ancestral protein sequence represented as the node to which the protein is joined. For example, it is estimated that an average of 0.22 amino acid substitution occurred at each position in the sequence of the AtHsp90-6 protein since it diverged from the common ancestor, leading to both it and the AtHsp90-5 protein. Branches without an associated substitution number have fewer than 0.01 substitution per position
Fig 2.
Fig 2.
Multiple sequence alignment of members of the A thaliana Hsp90 family. The multiple alignment was generated using CLUSTALX. Positions that share greater than 70% amino acid identities are indicated in red, and positions that share greater than 70% similarity are shown in blue. The positions of conserved functional domains are named above the aligned sequences. Positions of highly related, ungapped sequences that can be considered as being characteristic of the Hsp90 family were determined by searching the BLOCKS database with AtHsp90-2 as a reference sequence. The Blocks, indicated by BLOCK_A to BLOCK_J names, are positioned on the multiple sequence alignment, using AtHsp90-2 sequence as a reference. Only AtHsp90-1 to AtHsp90-4 sequences contain all 10 BLOCKS characteristic of the Hsp90 family of proteins
Fig 2.
Fig 2.
Continued
Fig 2.
Fig 2.
Continued
See this image and copyright information in PMC

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