Plant Transcription Factor Database
Previous version: v3.0
Phalaenopsis equestris
HSF Family
Species TF ID Description
PEQU_00926HSF family protein
PEQU_00991HSF family protein
PEQU_07498HSF family protein
PEQU_07685HSF family protein
PEQU_08461HSF family protein
PEQU_09454HSF family protein
PEQU_10205HSF family protein
PEQU_10728HSF family protein
PEQU_11784HSF family protein
PEQU_14552HSF family protein
PEQU_17243HSF family protein
PEQU_18378HSF family protein
PEQU_21655HSF family protein
PEQU_25301HSF family protein
PEQU_28733HSF family protein
PEQU_29621HSF family protein
PEQU_29628HSF family protein
PEQU_38704HSF family protein
PEQU_40212HSF family protein
PEQU_40267HSF family protein
HSF Family Introduction

Heat stress transcription factors (Hsfs) are the major regulators of the plant heat stress (hs) response. Sequencing of the Arabidopsis genome revealed the existence of 21 open-reading frames (ORFs) encoding putative Hsfs assigned to classes A-C. Here we present results of a functional genomics approach to the Arabidopsis Hsf family focused on the analysis of their C-terminal domains (CTDs) harboring conserved modules for their function as transcription factors and their intracellular localization. Using reporter assays in tobacco protoplasts and yeast as well as glutathione-S-transferase (GST) pull-down assays, we demonstrate that short peptide motifs enriched with aromatic and large hydrophobic amino acid (aa) residues embedded in an acidic surrounding (AHA motifs) are essential for transcriptional activity of class A Hsfs. In contrast to this, class B and C Hsfs lack AHA motifs and have no activator function on their own. We also provide evidence for the function of a leucine (Leu)-rich region centered around a conserved QMGΦL motif at the very C-terminus as a nuclear export signal (NES) of class A Hsfs. Sequence comparison indicates that the combination of a C-terminal AHA motif with the consensus sequence FWxxF/L,F/I/L as well as the adjacent NES represents a signature domain for plant class A Hsfs, which allowed to identify more than 60 new Hsfs from the expressed sequence tag (EST) database.

Kotak S, Port M, Ganguli A, Bicker F, von Koskull-Doring P.
Characterization of C-terminal domains of Arabidopsis heat stress transcription factors (Hsfs) and identification of a new signature combination of plant class A Hsfs with AHA and NES motifs essential for activator function and intracellular localization.
Plant J, 2004. 39(1): p. 98-112.
PMID: 15200645