Heat stress transcription factor A-1E (HSFA1E) is a class A heat shock factor and sequence-specific DNA-binding transcriptional activator. Like other HSF family members, it recognizes heat shock promoter elements through its conserved HSF DNA-binding domain, is annotated to both cytoplasm and nucleus, and acts in transcriptional regulation of stress-responsive genes. Its molecular transcription-factor activity is better established than any HSFA1E-specific biological process, and HSFA1E appears to play a secondary, partially redundant role in the heat response relative to the better-characterized HSFA1A/B/D master regulators.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003700 DNA-binding transcription factor activity | IBA GO_REF:0000033 | ACCEPT | Summary: HSFA1E functions as a DNA-binding transcription factor that specifically recognizes heat shock elements (HSE) with the sequence 5'-AGAAnnTTCT-3' and activates transcription of stress-responsive genes. This is a core molecular function conserved across all HSFA1 family members. Reason: This annotation accurately represents the primary molecular function of HSFA1E. The deep research document extensively describes HSFA1E's role as a transcriptional activator with sequence-specific DNA binding activity, supported by structural and functional studies showing the conserved DNA-binding domain and trimerization-dependent activation mechanism. UniProt entry confirms "Transcriptional activator that specifically binds DNA sequence 5'-AGAAnnTTCT-3'". Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md HSFA1E possesses a highly conserved modular protein architecture typical of eukaryotic heat shock factors. At the amino-terminal end of the protein lies the DNA-binding domain (DBD), which is the most evolutionarily conserved component of all heat shock transcription factors. This domain comprises a trimerization interface consisting of three Ξ±-helical bundles and four antiparallel Ξ²-sheets arranged in a characteristic winged-helix structure. The precise three-dimensional architecture of this domain endows HSFA1E with remarkable specificity for recognizing the palindromic DNA sequence 5'-AGAAnnTTCT-3', which constitutes the canonical heat shock element (HSE). file:ARATH/AT3G02990/AT3G02990-uniprot.txt Transcriptional activator that specifically binds DNA sequence 5'-AGAAnnTTCT-3' known as heat shock promoter elements (HSE). |
| GO:0000978 RNA polymerase II cis-regulatory region sequence-specific DNA binding | IBA GO_REF:0000033 | ACCEPT | Summary: HSFA1E binds to RNA polymerase II cis-regulatory regions containing heat shock elements (HSE) in the promoters of target genes to activate their transcription. This is a core molecular function. Reason: This annotation accurately captures HSFA1E's mechanism of action. The deep research describes how HSFA1E trimers bind to HSE sequences in promoter regions and recruit RNA polymerase II transcriptional machinery. This is consistent with its role in activating transcription of heat shock proteins, HSFA2, DREB2A, and other stress-responsive genes through promoter binding. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md Once activated, HSFA1E trimers bind to heat shock elements in the promoter regions of target genes and recruit transcriptional machinery to initiate their expression. The AHA motif is characterized by the presence of aromatic, large hydrophobic, and acidic amino acid residues arranged in a pattern that enables interaction with transcriptional co-activators and components of the RNA polymerase II transcriptional machinery. file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md HSFA1d and HSFA1e specifically regulate the expression of HSFA2 through binding to a heat shock element cluster in the 5β²-flanking region of the HSFA2 gene. |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: HSFA1E localizes to the nucleus, particularly under stress conditions, where it binds to DNA and activates transcription. This is a core localization for its transcription factor function. Reason: Nuclear localization is well-established for HSFA1E. The protein contains a nuclear localization signal (NLS) and accumulates in the nucleus upon stress activation. Deep research describes stress-dependent nuclear accumulation with rapid kinetics (within minutes of heat stress). UniProt confirms nuclear localization and experimental evidence from PMID:21931939 demonstrates nuclear accumulation. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md HSFA1E contains a nuclear localization signal (NLS) positioned adjacent to its oligomerization domain. The nuclear localization of HSFA1E becomes dramatically enhanced during heat stress, as trimerized active HSFA1E is released from cytoplasmic chaperones and translocates to the nucleus where it can access its target genes. This stress-dependent nuclear accumulation is highly dynamic, with HSFA1E accumulating in the nucleus within minutes of heat stress exposure. PMID:21931939 HsfA1 protein accumulation in the nucleus was negatively regulated by their interactions with HSP90, and other factors potentially strongly activate the HsfA1 proteins under HS stress. |
| GO:0034605 cellular response to heat | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: HSFA1E participates in cellular response to heat as a member of the HSFA1 family, but available synthesis indicates its heat-response contribution is weaker than the better-characterized HSFA1A/B/D regulators. Reason: The IBA annotation is plausible for an HSF-family transcription factor, but HSFA1E-specific process evidence in the cached local inputs is limited. The heat-response term should therefore be retained as non-core rather than used to claim that HSFA1E is a primary heat-shock master regulator. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md HSFA1e plays a more secondary role compared to its paralogs in the core heat stress response, particularly relative to HSFA1a, HSFA1b, and HSFA1d. Analysis of multiple hsfa1 mutant combinations has demonstrated that HSFA1a, HSFA1b, and HSFA1d function as the primary master regulators of the heat shock response, with these three genes together controlling the expression of more than 65% of all heat stress-induced genes in Arabidopsis. In contrast, analysis of quadruple knockout mutants (hsfa1a/hsfa1b/hsfa1d/hsfa1e) versus triple knockouts lacking only HSFA1e (hsfa1a/hsfa1b/hsfa1d) revealed that HSFA1e makes a relatively minor contribution to the acquisition of thermotolerance upon heat acclimation. |
| GO:0003677 DNA binding | IEA GO_REF:0000043 | ACCEPT | Summary: HSFA1E has DNA binding activity through its conserved DNA-binding domain (DBD) containing winged-helix structure that binds heat shock elements. Reason: This is an accurate but general molecular function annotation. HSFA1E possesses a highly conserved DNA-binding domain with a winged-helix structure that specifically binds to HSE sequences. This is supported by structural and functional data and is a fundamental property of the protein. The more specific annotation GO:0000978 (RNA polymerase II cis-regulatory region sequence-specific DNA binding) provides additional detail, but this general DNA binding annotation is also correct. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md At the amino-terminal end of the protein lies the DNA-binding domain (DBD), which is the most evolutionarily conserved component of all heat shock transcription factors. This domain comprises a trimerization interface consisting of three Ξ±-helical bundles and four antiparallel Ξ²-sheets arranged in a characteristic winged-helix structure. file:ARATH/AT3G02990/AT3G02990-uniprot.txt DNA_BIND 21..115. HSF_DNA-bind domain. |
| GO:0003700 DNA-binding transcription factor activity | IEA GO_REF:0000002 | ACCEPT | Summary: Duplicate of IBA annotation with same term. HSFA1E functions as DNA-binding transcription factor. Reason: This is a duplicate annotation of GO:0003700 already annotated with IBA evidence (GO_REF:0000033). Both annotations are correct and represent core molecular function. The IEA annotation is based on InterPro domain mapping which correctly identifies the HSF DNA-binding domain. Having multiple evidence codes for the same accurate annotation is acceptable in GO. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-uniprot.txt Transcriptional activator that specifically binds DNA sequence 5'-AGAAnnTTCT-3' known as heat shock promoter elements (HSE). |
| GO:0005634 nucleus | IEA GO_REF:0000044 | ACCEPT | Summary: Duplicate nuclear localization annotation. HSFA1E localizes to nucleus. Reason: This is a duplicate annotation of GO:0005634 already annotated with IBA evidence. The IEA annotation is based on UniProt subcellular location mapping. Nuclear localization is well-supported and this duplication with different evidence codes is acceptable. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-uniprot.txt SUBCELLULAR LOCATION: Cytoplasm. Nucleus. |
| GO:0005737 cytoplasm | IEA GO_REF:0000044 | ACCEPT | Summary: HSFA1E localizes to the cytoplasm under non-stress conditions where it is maintained in an inactive state through interactions with chaperone proteins HSP70/HSP90. This is part of its regulatory mechanism. Reason: Cytoplasmic localization is well-documented and functionally important for HSFA1E regulation. Under non-stress conditions, HSFA1E is predominantly cytoplasmic where it is sequestered by molecular chaperones (Hsp70/Hsp90). Upon stress, the protein undergoes nuclear translocation. The protein contains both nuclear localization and nuclear export signals, enabling dynamic shuttling between cytoplasm and nucleus. UniProt confirms both cytoplasmic and nuclear localization. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md HSFA1E functions as a shuttling protein that dynamically translocates between the cytoplasm and nucleus in response to cellular stress. Under non-stressed conditions, HSFA1E is predominantly localized in the cytoplasm, where it is maintained in an inactive state through interactions with chaperone proteins. These chaperone proteins bind to HSFA1E in the cytoplasm and functionally repress its transcriptional activity through multiple mechanisms. file:ARATH/AT3G02990/AT3G02990-uniprot.txt SUBCELLULAR LOCATION: Cytoplasm. Nucleus. |
| GO:0006355 regulation of DNA-templated transcription | IEA GO_REF:0000002 | ACCEPT | Summary: HSFA1E regulates DNA-templated transcription by binding to heat shock elements in promoters and activating stress-responsive gene expression. This is a core biological process for the protein. Reason: This annotation accurately describes the core biological process function of HSFA1E. As a transcription factor, HSFA1E regulates DNA-templated transcription by binding to HSE sequences in target gene promoters and activating their expression. This includes genes encoding heat shock proteins, HSFA2, DREB2A, and other stress-responsive genes. The annotation is appropriate as a general biological process term. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md Once activated, HSFA1E trimers bind to heat shock elements in the promoter regions of target genes and recruit transcriptional machinery to initiate their expression. HSFA1E and other HSFA1 proteins directly activate the transcription of a large number of genes encoding heat shock proteins and other stress-protective proteins. |
| GO:0043565 sequence-specific DNA binding | IEA GO_REF:0000002 | ACCEPT | Summary: HSFA1E exhibits sequence-specific DNA binding through recognition of the palindromic heat shock element (HSE) sequence 5'-AGAAnnTTCT-3'. This is a core molecular function. Reason: This annotation correctly describes HSFA1E's sequence-specific DNA binding capability. The protein specifically recognizes the HSE palindromic sequence through its conserved DNA-binding domain with winged-helix structure. The specificity is achieved through direct base-specific hydrogen bonding in the major groove and DNA shape recognition mechanisms. This is well-supported by structural and functional studies. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-deep-research-perplexity.md The precise three-dimensional architecture of this domain endows HSFA1E with remarkable specificity for recognizing the palindromic DNA sequence 5'-AGAAnnTTCT-3', which constitutes the canonical heat shock element (HSE). The DNA-binding domain achieves its specificity through a combination of direct base-specific hydrogen bonding interactions formed in the major groove of DNA and indirect recognition mechanisms that exploit DNA shape. file:ARATH/AT3G02990/AT3G02990-uniprot.txt Transcriptional activator that specifically binds DNA sequence 5'-AGAAnnTTCT-3' known as heat shock promoter elements (HSE). |
| GO:0005634 nucleus | ISM GO_REF:0000122 | ACCEPT | Summary: Another duplicate nuclear localization annotation based on AtSubP analysis. HSFA1E localizes to nucleus. Reason: This is a third annotation for nuclear localization (GO:0005634), this time with ISM evidence from AtSubP subcellular localization prediction analysis. Nuclear localization is well-established through multiple lines of evidence including experimental data (IDA), phylogenetic inference (IBA), and now sequence-based prediction (ISM). All support the same correct localization. Supporting Evidence: file:ARATH/AT3G02990/AT3G02990-uniprot.txt SUBCELLULAR LOCATION: Cytoplasm. Nucleus. MOTIF 223..227 Nuclear localization signal. |
| GO:0005634 nucleus | IDA PMID:21931939 Arabidopsis HsfA1 transcription factors function as the main... | ACCEPT | Summary: Fourth duplicate nuclear localization annotation, this time with experimental evidence (IDA) from PMID:21931939 demonstrating HsfA1 protein nuclear accumulation. Reason: This is a fourth annotation for nuclear localization (GO:0005634), now with direct experimental evidence (IDA) from PMID:21931939. The cached abstract supports HsfA1 protein nuclear accumulation as a group-level property and HSP90-dependent negative regulation. It supports HSFA1E nuclear localization in the context of the HsfA1 set without requiring a stronger HSFA1E-specific localization claim from the available text. Supporting Evidence: PMID:21931939 HsfA1 protein accumulation in the nucleus was negatively regulated by their interactions with HSP90, and other factors potentially strongly activate the HsfA1 proteins under HS stress. |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:11118137 Arabidopsis transcription factors: genome-wide comparative a... | ACCEPT | Summary: Third duplicate annotation for DNA-binding transcription factor activity, this time with ISS evidence from genome-wide transcription factor analysis. Reason: This is a third annotation for GO:0003700 (DNA-binding transcription factor activity), now with ISS (Inferred from Sequence or Structural Similarity) evidence from PMID:11118137. This paper by Riechmann et al. (2000) performed a genome-wide comparative analysis of Arabidopsis transcription factors, identifying HSFA1E as a member of the HSF family based on conserved DNA-binding domain. The annotation is correct and the ISS evidence complements the IBA and IEA evidence already present. Supporting Evidence: PMID:11118137 Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes |
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