FEATURES

FAMILY

DESCRIPTION

Also known as HSF1_HUMAN, HSF1, HSTF1. Functions as a stress-inducible and DNA-binding transcription factor that plays a central role in the transcriptional activation of the heat shock response (HSR), leading to the expression of a large class of molecular chaperones heat shock proteins (HSPs) that protect cells from cellular insults' damage (PubMed:1871105, PubMed:11447121, PubMed:1986252, PubMed:7760831, PubMed:7623826, PubMed:8946918, PubMed:8940068, PubMed:9341107, PubMed:9121459, PubMed:9727490, PubMed:9499401, PubMed:9535852, PubMed:12659875, PubMed:12917326, PubMed:15016915, PubMed:25963659, PubMed:26754925). In unstressed cells, is present in a HSP90-containing multichaperone complex that maintains it in a non-DNA-binding inactivated monomeric form (PubMed:9727490, PubMed:11583998, PubMed:16278218). Upon exposure to heat and other stress stimuli, undergoes homotrimerization and activates HSP gene transcription through binding to site-specific heat shock elements (HSEs) present in the promoter regions of HSP genes (PubMed:1871105, PubMed:1986252, PubMed:8455624, PubMed:7935471, PubMed:7623826, PubMed:8940068, PubMed:9727490, PubMed:9499401, PubMed:10359787, PubMed:11583998, PubMed:12659875, PubMed:16278218, PubMed:25963659, PubMed:26754925). Activation is reversible, and during the attenuation and recovery phase period of the HSR, returns to its unactivated form (PubMed:11583998, PubMed:16278218). Binds to inverted 5'-NGAAN-3' pentamer DNA sequences (PubMed:1986252, PubMed:26727489). Binds to chromatin at heat shock gene promoters (PubMed:25963659). Plays also several other functions independently of its transcriptional activity. Involved in the repression of Ras-induced transcriptional activation of the c-fos gene in heat-stressed cells (PubMed:9341107). Positively regulates pre-mRNA 3'-end processing and polyadenylation of HSP70 mRNA upon heat-stressed cells in a symplekin (SYMPK)-dependent manner (PubMed:14707147). Plays a role in nuclear export of stress-induced HSP70 mRNA (PubMed:17897941). Plays a role in the regulation of mitotic progression (PubMed:18794143). Plays also a role as a negative regulator of non-homologous end joining (NHEJ) repair activity in a DNA damage-dependent manner (PubMed:26359349). Involved in stress-induced cancer cell proliferation in a IER5-dependent manner (PubMed:26754925)., (Microbial infection) Plays a role in latent human immunodeficiency virus (HIV-1) transcriptional reactivation. Binds to the HIV-1 long terminal repeat promoter (LTR) to reactivate viral transcription by recruiting cellular transcriptional elongation factors, such as CDK9, CCNT1 and EP300. Monomer; cytoplasmic latent and transcriptionally inactive monomeric form in unstressed cells (PubMed:8455624, PubMed:7935376, PubMed:7935471, PubMed:7623826, PubMed:9222587, PubMed:9727490, PubMed:11583998). Homotrimer; in response to stress, such as heat shock, homotrimerizes and translocates into the nucleus, binds to heat shock element (HSE) sequences in promoter of heat shock protein (HSP) genes and acquires transcriptional ability (PubMed:8455624, PubMed:7935471, PubMed:7623826, PubMed:9222587, PubMed:9727490, PubMed:11583998, PubMed:26754925, PubMed:26727489). Interacts (via monomeric form) with FKBP4; this interaction occurs in unstressed cells (PubMed:11583998). Associates (via monomeric form) with HSP90 proteins in a multichaperone complex in unnstressed cell; this association maintains HSF1 in a non-DNA-binding and transcriptional inactive form by preventing HSF1 homotrimerization (PubMed:9727490, PubMed:11583998, PubMed:15661742, PubMed:16278218). Homotrimeric transactivation activity is modulated by protein-protein interactions and post-translational modifications (PubMed:11583998, PubMed:15016915, PubMed:16554823, PubMed:26754925). Interacts with HSP90AA1; this interaction is decreased in a IER5-dependent manner, promoting HSF1 accumulation in the nucleus, homotrimerization and DNA-binding activities (PubMed:26754925). Part (via regulatory domain in the homotrimeric form) of a large heat shock-induced HSP90-dependent multichaperone complex at least composed of FKBP4, FKBP5, HSP90 proteins, PPID, PPP5C and PTGES3; this association maintains the HSF1 homotrimeric DNA-bound form in a transcriptionally inactive form (PubMed:9727490, PubMed:11583998, PubMed:16278218). Interacts with BAG3 (via BAG domain); this interaction occurs in normal and heat-shocked cells promoting nuclear shuttling of HSF1 in a BAG3-dependent manner (PubMed:26159920). Interacts (via homotrimeric and hyperphosphorylated form) with FKBP4; this interaction occurs upon heat shock in a HSP90-dependent multichaperone complex (PubMed:11583998). Interacts (via homotrimeric form preferentially) with EEF1A proteins (PubMed:15016915). In heat shocked cells, stress-denatured proteins compete with HSF1 homotrimeric DNA-bound form for association of the HSP90-dependent multichaperone complex, and hence alleviating repression of HSF1-mediated transcriptional activity (PubMed:11583998). Interacts (via homotrimeric form preferentially) with DAXX; this interaction relieves homotrimeric HSF1 from repression of its transcriptional activity by HSP90-dependent multichaperone complex upon heat shock (PubMed:15016915). Interacts (via D domain and preferentially with hyperphosphorylated form) with JNK1; this interaction occurs under both normal growth conditions and immediately upon heat shock (PubMed:10747973). Interacts (via D domain and preferentially with hyperphosphorylated form) with MAPK3; this interaction occurs upon heat shock (PubMed:10747973). Interacts with IER5 (via central region); this interaction promotes PPP2CA-induced dephosphorylation on Ser-121, Ser-307, Ser-314, Thr-323 and Thr-367 and HSF1 transactivation activity (PubMed:25816751, PubMed:26496226, PubMed:26754925). Found in a ribonucleoprotein complex composed of the HSF1 homotrimeric form, translation elongation factor eEF1A proteins and non-coding RNA heat shock RNA-1 (HSR1); this complex occurs upon heat shock and stimulates HSF1 DNA-binding activity (PubMed:16554823). Interacts (via transactivation domain) with HSPA1A/HSP70 and DNAJB1; these interactions result in the inhibition of heat shock- and HSF1-induced transcriptional activity during the attenuation and recovery phase from heat shock (PubMed:7935376, PubMed:9222587, PubMed:9499401). Interacts (via Ser-303 and Ser-307 phosphorylated form) with YWHAE; this interaction promotes HSF1 sequestration in the cytoplasm in an ERK-dependent manner (PubMed:12917326). Found in a complex with IER5 and PPP2CA (PubMed:26754925). Interacts with TPR; t

EXTERNAL LINKS

HSF1

Heat shock factor protein 1

HSF1

Molecular Synopsis