While ATF6α plays a central role in the endoplasmic reticulum (ER) stress response, the function of its homologue ATF6β remains elusive, especially in the central nervous system (CNS). Here, we demonstrate that ATF6β is highly expressed in the hippocampus of the brain, and specifically regulates the expression of calreticulin (CRT), a molecular chaperone in the ER with a high Ca2+-binding capacity. CRT expression was reduced to ~ 50% in the CNS of Atf6b−/− mice under both normal and ER stress conditions. Analysis using cultured hippocampal neurons revealed that ATF6β deficiency reduced Ca2+ stores in the ER and enhanced ER stress-induced death. The higher levels of death in Atf6b−/− neurons were recovered by ATF6β and CRT overexpressions, or by treatment with Ca2+-modulating reagents such as BAPTA-AM and 2-APB, and with an ER stress inhibitor salubrinal. In vivo, kainate-induced neuronal death was enhanced in the hippocampi of Atf6b−/− and Calr+/− mice, and restored by administration of 2-APB and salubrinal. These results suggest that the ATF6β-CRT axis promotes neuronal survival under ER stress and excitotoxity by improving intracellular Ca2+ homeostasis.

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No competing interests reported.
This is a list of supplementary files associated with this preprint. Click to download.
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Posted 15 Mar, 2021
On 28 Apr, 2021
Received 29 Mar, 2021
On 26 Mar, 2021
On 11 Mar, 2021
Invitations sent on 11 Mar, 2021
On 04 Mar, 2021
On 03 Mar, 2021
On 03 Mar, 2021
On 01 Mar, 2021
Posted 15 Mar, 2021
On 28 Apr, 2021
Received 29 Mar, 2021
On 26 Mar, 2021
On 11 Mar, 2021
Invitations sent on 11 Mar, 2021
On 04 Mar, 2021
On 03 Mar, 2021
On 03 Mar, 2021
On 01 Mar, 2021
While ATF6α plays a central role in the endoplasmic reticulum (ER) stress response, the function of its homologue ATF6β remains elusive, especially in the central nervous system (CNS). Here, we demonstrate that ATF6β is highly expressed in the hippocampus of the brain, and specifically regulates the expression of calreticulin (CRT), a molecular chaperone in the ER with a high Ca2+-binding capacity. CRT expression was reduced to ~ 50% in the CNS of Atf6b−/− mice under both normal and ER stress conditions. Analysis using cultured hippocampal neurons revealed that ATF6β deficiency reduced Ca2+ stores in the ER and enhanced ER stress-induced death. The higher levels of death in Atf6b−/− neurons were recovered by ATF6β and CRT overexpressions, or by treatment with Ca2+-modulating reagents such as BAPTA-AM and 2-APB, and with an ER stress inhibitor salubrinal. In vivo, kainate-induced neuronal death was enhanced in the hippocampi of Atf6b−/− and Calr+/− mice, and restored by administration of 2-APB and salubrinal. These results suggest that the ATF6β-CRT axis promotes neuronal survival under ER stress and excitotoxity by improving intracellular Ca2+ homeostasis.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7
No competing interests reported.
This is a list of supplementary files associated with this preprint. Click to download.
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