Heat shock factor

Heat shock factor (HSF), in molecular biology, is the name given to transcription factors that regulate the expression of the heat shock proteins.^[1]^[2] A typical example is the heat shock factor of Drosophila melanogaster.^[3]

Function

Heat shock factors (HSF) are transcriptional activators of heat shock genes.^[3] These activators bind specifically to Heat Shock sequence Elements (HSE) throughout the genome^[4] whose consensus-sequence is a tandem array of three oppositely oriented "AGAAN" motifs or a degenerate version thereof. Under non-stressed conditions, Drosophila HSF is a nuclear-localized unbound monomer, whereas heat shock activation results in trimerization and binding to the HSE.^[5] The Heat Shock sequence Element is highly conserved from yeast to humans.^[6]

Heat shock factor 1 (HSF-1) is the major regulator of heat shock protein transcription in eukaryotes. In the absence of cellular stress, HSF-1 is inhibited by association with heat shock proteins and is therefore not active. Cellular stresses, such as increased temperature, can cause proteins in the cell to misfold. Heat shock proteins bind to the misfolded proteins and dissociate from HSF-1. This allows HSF1 to form trimers and translocate to the cell nucleus and activate transcription.^[7] Its function is not only critical to overcome the proteotoxic effects of thermal stress, but also needed for proper animal development and the overall survival of cancer cells.^[8]^[9]

Structure

Each HSF monomer contains one C-terminal and three N-terminal leucine zipper repeats.^[10] Point mutations in these regions result in disruption of cellular localisation, rendering the protein constitutively nuclear in humans.^[5] Two sequences flanking the N-terminal zippers fit the consensus of a bi-partite nuclear localization signal (NLS). Interaction between the N- and C-terminal zippers may result in a structure that masks the NLS sequences: following activation of HSF, these may then be unmasked, resulting in relocalisation of the protein to the nucleus.^[10] The DNA-binding component of HSF lies to the N-terminus of the first NLS region, and is referred to as the HSF domain.

Isoforms

Humans express the following heat shock factors:

gene	protein
HSF1	heat shock transcription factor 1
HSF2	heat shock transcription factor 2
HSF2BP	heat shock transcription factor 2 binding protein
HSF4	heat shock transcription factor 4
HSF5	heat shock transcription factor family member 5
HSFX1	heat shock transcription factor family, X linked 1
HSFX2	heat shock transcription factor family, X linked 2
HSFY1	heat shock transcription factor, Y-linked 1
HSFY2	heat shock transcription factor, Y-linked 2

References

↑ Sorger PK (May 1991). "Heat shock factor and the heat shock response". Cell. 65 (3): 363–6. doi:10.1016/0092-8674(91)90452-5. PMID 2018972.
↑ Morimoto RI (March 1993). "Cells in stress: transcriptional activation of heat shock genes". Science. 259 (5100): 1409–10. doi:10.1126/science.8451637. PMID 8451637.
1 2 Clos J, Westwood JT, Becker PB, Wilson S, Lambert K, Wu C (November 1990). "Molecular cloning and expression of a hexameric Drosophila heat shock factor subject to negative regulation". Cell. 63 (5): 1085–97. doi:10.1016/0092-8674(90)90511-C. PMID 2257625.
↑ Guertin, MJ; Lis, JT (Sep 2010). "Chromatin landscape dictates HSF binding to target DNA elements.". PLoS Genetics. 6 (9): e1001114. doi:10.1371/journal.pgen.1001114. PMC 2936546. PMID 20844575.
1 2 Rabindran SK, Giorgi G, Clos J, Wu C (August 1991). "Molecular cloning and expression of a human heat shock factor, HSF1". Proc. Natl. Acad. Sci. U.S.A. 88 (16): 6906–10. doi:10.1073/pnas.88.16.6906. PMC 52202. PMID 1871105.
↑ Guertin, MJ; Petesch SJ; Zobeck KL; Min IM; Lis JT. (2010). "Drosophila heat shock system as a general model to investigate transcriptional regulation.". Cold Spring Harb Symp Quant Biol. 75: 1–9. doi:10.1101/sqb.2010.75.039. PMID 21467139.
↑ Prahlad, V, Morimoto RI (Dec 2008). "Integrating the stress response: lessons for neurodegenerative diseases from C. elegans". Trends in Cell Biology. 19 (2): 52–61. doi:10.1016/j.tcb.2008.11.002. PMID 19112021.
↑ Salamanca, HH; Fuda N; Shi H; Lis JT. (2011). "An RNA aptamer perturbs heat shock transcription factor activity in Drosophila melanogaster". Nucleic Acids Research. 39 (15): 6729–6740. doi:10.1093/nar/gkr206. PMID 21576228.
↑ Salamanca, HH; Antonyak MA; Cerione RA; Shi H; Lis JT. (2014). "Inhibiting heat shock factor 1 in human cancer cells with a potent RNA aptamer.". PLOS ONE. 9 (5): e96330. doi:10.1371/journal.pone.0096330. PMC 4011729. PMID 24800749.
1 2 Schuetz TJ, Gallo GJ, Sheldon L, Tempst P, Kingston RE (August 1991). "Isolation of a cDNA for HSF2: evidence for two heat shock factor genes in humans". Proc. Natl. Acad. Sci. U.S.A. 88 (16): 6911–5. doi:10.1073/pnas.88.16.6911. PMC 52203. PMID 1871106.

This article incorporates text from the public domain Pfam and InterPro IPR000232

Transcription factors and intracellular receptors

(1) Basic domains

(1.1) Basic leucine zipper (bZIP)	Activating transcription factor AATF 1 2 3 4 5 6 7 AP-1 c-Fos FOSB FOSL1 FOSL2 JDP2 c-Jun JUNB JunD BACH 1 2 BATF BLZF1 C/EBP α β γ δ ε ζ CREB 1 3 L1 CREM DBP DDIT3 GABPA HLF MAF B F G K NFE 2 L1 L2 L3 NFIL3 NRL NRF 1 2 3 XBP1

(1.2) Basic helix-loop-helix (bHLH)	ATOH1 AhR AHRR ARNT ASCL1 BHLH 2 3 9 ARNTL ARNTL ARNTL2 CLOCK EPAS1 FIGLA HAND 1 2 HES 5 6 HEY 1 2 L HES1 HIF 1A 3A ID 1 2 3 4 LYL1 MESP2 MXD4 MYCL1 MYCN Myogenic regulatory factors MyoD Myogenin MYF5 MYF6 Neurogenins 1 2 3 NeuroD 1 2 NPAS 1 2 3 OLIG 1 2 Pho4 Scleraxis SIM 1 2 TAL 1 2 Twist USF1

(1.3) bHLH-ZIP	AP-4 MAX MXD3 MITF MNT MLX MXI1 Myc SREBP 1 2

(1.4) NF-1	NFI A B C X SMAD R-SMAD 1 2 3 5 9 I-SMAD 6 7 4)

(1.5) RF-X	RFX 1 2 3 4 5 6 ANK

(1.6) Basic helix-span-helix (bHSH)	AP-2 α β γ δ ε

(2) Zinc finger DNA-binding domains

(2.1) Nuclear receptor (Cys₄)

subfamily 1	Thyroid hormone α β CAR FXR LXR α β PPAR α β/δ γ PXR RAR α β γ ROR α β γ Rev-ErbA α β VDR

subfamily 2	COUP-TF (I II Ear-2 HNF4 α γ PNR RXR α β γ Testicular receptor 2 4 TLX

subfamily 3	Steroid hormone Androgen Estrogen α β Glucocorticoid Mineralocorticoid Progesterone Estrogen related α β γ

subfamily 4	NUR NGFIB NOR1 NURR1

subfamily 5	LRH-1 SF1

subfamily 6	GCNF

subfamily 0	DAX1 SHP

(2.2) Other Cys₄

GATA
- 1
- 2
- 3
- 4
- 5
- 6
MTA
- 1
- 2
- 3
TRPS1

(2.3) Cys₂His₂

General transcription factors
- TFIIA
- TFIIB
- TFIID
- TFIIE
  - 1
  - 2
- TFIIF
- 1
- 2
  - TFIIH
  - 1
  - 2
  - 4
  - 2I
  - 3A
  - 3C1
  - 3C2

ATBF1
BCL
- 6
- 11A
- 11B
CTCF
E4F1
EGR
- 1
- 2
- 3
- 4
ERV3
GFI1
GLI-Krüppel family
- 1
- 2
- 3
- REST
- S1
- S2
- YY1
HIC
- 1
- 2
HIVEP
- 1
- 2
- 3
IKZF
- 1
- 2
- 3
ILF
- 2
- 3
KLF
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 17
MTF1
MYT1
OSR1
PRDM9
SALL
- 1
- 2
- 3
- 4
SP
- 1
- 2
- 4
- 7
- 8
TSHZ3
WT1
Zbtb7
- 7A
- 7B
ZBTB
- 11
- 16
- 17
- 20
- 32
- 33
- 40
zinc finger
- 3
- 7
- 9
- 10
- 19
- 22
- 24
- 33B
- 34
- 35
- 41
- 43
- 44
- 51
- 74
- 143
- 146
- 148
- 165
- 202
- 217
- 219
- 238
- 239
- 259
- 267
- 268
- 281
- 295
- 300
- 318
- 330
- 346
- 350
- 365
- 366
- 384
- 423
- 451
- 452
- 471
- 593
- 638
- 644
- 649
- 655

(2.4) Cys₆

HIVEP1

(2.5) Alternating composition

AIRE
DIDO1
GRLF1
ING
- 1
- 2
- 4
JARID
- 1A
- 1B
- 1C
- 1D
- 2
JMJD1B

(2.6) WRKY

WRKY

(3) Helix-turn-helix domains

(3.1) Homeodomain	ARX CDX 1 2 CRX CUTL1 DBX 1 2 DLX 3 4 5 EMX 1 2 EN 1 2 FHL 1 2 3 HESX1 HHEX HLX Homeobox A1 A2 A3 A4 A5 A7 A9 A10 A11 A13 B1 B2 B3 B4 B5 B6 B7 B8 B9 B13 C4 C5 C6 C8 C9 C10 C11 C12 C13 D1 D3 D4 D8 D9 D10 D11 D12 D13 HOPX IRX 1 2 3 4 5 6 MKX LMX 1A 1B MEIS 1 2 MEOX2 MNX1 MSX 1 2 NANOG NKX 2-1 2-2 2-3 2-5 3-1 3-2 6-1 6-2 NOBOX PBX 1 2 3 PHF 1 3 6 8 10 16 17 20 21A PHOX 2A 2B PITX 1 2 3 POU domain PIT-1 BRN-3: A B C Octamer transcription factor: 1 2 3/4 6 7 11 OTX 1 2 PDX1 SATB2 SHOX2 SIX 1 2 3 4 5 VAX1 ZEB 1 2

(3.2) Paired box	PAX 1 2 3 4 5 6 7 8 9 PRRX 1 2 RAX

(3.3) Fork head / winged helix	E2F 1 2 3 4 5 FOX proteins A1 A2 A3 C1 C2 D3 D4 E1 E3 F1 G1 H1 I1 J1 J2 K1 K2 L2 M1 N1 N3 O1 O3 O4 P1 P2 P3 P4

(3.4) Heat shock factors	HSF 1 2 4

(3.5) Tryptophan clusters	ELF 2 4 5 EGF ELK 1 3 4 ERF ETS 1 2 ERG SPIB ETV 1 4 5 6 FLI1 Interferon regulatory factors 1 2 3 4 5 6 7 8 MYB MYBL2

(3.6) TEA domain	transcriptional enhancer factor 1 2 3 4

(4) β-Scaffold factors with minor groove contacts

(4.1) Rel homology region	NF-κB NFKB1 NFKB2 REL RELA RELB NFAT C1 C2 C3 C4 5

(4.2) STAT	STAT 1 2 3 4 5 6

(4.3) p53	p53 TBX 1 2 3 5 19 21 22 TBR1 TBR2 TFT MYRF TP63

(4.4) MADS box	Mef2 A B C D SRF

(4.6) TATA-binding proteins	TBP TBPL1

(4.7) High-mobility group	BBX HMGB 1 2 3 4 HMGN 1 2 3 4 HNF 1A 1B LEF1 SOX 1 2 3 4 5 6 8 9 10 11 12 13 14 15 18 21 SRY SSRP1 TCF 3 4 TOX 1 2 3 4

(4.9) Grainyhead	TFCP2

(4.10) Cold-shock domain	CSDA YBX1

(4.11) Runt	CBF CBFA2T2 CBFA2T3 RUNX1 RUNX2 RUNX3 RUNX1T1

(0) Other transcription factors

(0.2) HMGI(Y)	HMGA 1 2 HBP1

(0.3) Pocket domain	Rb RBL1 RBL2

(0.5) AP-2/EREBP-related factors	Apetala 2 EREBP B3

(0.6) Miscellaneous	ARID 1A 1B 2 3A 3B 4A CAP IFI 16 35 MLL 2 3 T1 MNDA NFY A B C Rho/Sigma

see also transcription factor/coregulator deficiencies

This article is issued from Wikipedia - version of the 11/12/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.