eEF1A1 coordinates different levels of HSP70 expression during heat stress to promote cell survival

eEF1A1 coordinates different levels of HSP70 expression during heat stress to promote cell survival

1. eEF1A1 is a regulator of the adaptation to heat stress

   • Fig1a: eEF1A1 knockdown reduces Hsp70 expression during heat stress
   • Fig1b: eEF1A1 knockdown reduces cell survival during heat stress

2. eEF1A1 is a specific transcriptional regulator of HSP70 expression

   • Fig1c: eEF1A1 knockdown reduces Hsp70 mRNA expression during heat stress
   • Fig1d: eEF1A1 knockdown reduces RNA Pol II occupancy of an HSP70 gene (but not of an unrelated control gene)
   • Fig1e/f: eEF1A1 knockdown reduces the number and intensity of HSP70 transcription sites

3. eEF1A1 regulates HSF1 activity in transcriptionally active sites during heat stress, by interacting with it in a promoter-bound complex

   • eEF1A1 regulates HSF1 activity by interacting with it in a promoter-bound complex
     • eEF1A1 regulates HSF1 activity by interacting with it
       • eEF1A1 regulates HSF1 activity
         • Fig2a: eEF1A1 knockdown reduces binding of HSF1 to a synthetic HSP70 promoter fragment
         • Fig2b: eEF1A1 knockdown reduces HSF1 promoter occupancy in vivo
       • Fig2c: eEF1A1 interacts with HSF1 in vivo
       • Fig2d: eEF1A1-HSF1 complexes bind to a synthetic HSP70 promoter fragment
     • Fig2f: eEF1A1 itself binds to synthetic HSP70 promoter DNA
     • Fig2e: eEF1A1 specifically binds to HSP70 promoters in vitro
     • Fig3a-c: eEF1A1 localises to HSP70 transcription sites during heat stress in vivo
   • eEF1A1 is recruited to transcriptionally active sites during heat stress
     • Fig3d: eEF1A1 binding to HSP70 transcription sites is dependent on ongoing transcription
     • Fig3e: eEF1A1 directly binds to RNA pol II

4. eEF1A1 controls HSP70 translation by binding to it

   • Fig5d: eEF1A1 colocalises with HSP70 mRNA in the cytoplams during heat stress
   • Fig5e: eEF1A1 knockdown reduces HSP70 mRNA translation during heat stress

5. Fig5a-c: eEF1A1 knockdown impairs HSP70 mRNA export

6. eEF1A1 promotes HSP70 mRNA stability by binding to it

   • eEF1A1 binds to HSP70 mRNA
     • Fig4a,b: eEF1A1 remains bound to HSP70 mRNA following transcription
     • Fig4c: eEF1A1 binds to the 3'-UTR of HSP70 mRNA in vitro
   • eEF1A1 controls HSP70 mRNA stability
     • Fig4e: eEF1A1 knockdown reduces HSP70 mRNA half-life
     • Fig4f: eEF1A1 knckdown reduces the expression of a reporter gene containing the HSP70 promoter and 3'-UTR