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Temperature-Dependent Upregulation of Per2 Protein Expression Is Mediated by eIF2α Kinases PERK and PKR through PI3K Activation. | LitMetric

AI Article Synopsis

  • Temperature influences the core clock gene Per2, which is crucial for aligning the circadian clock with body temperature cycles.
  • Previous research indicated that the PI3K signaling pathway plays a role in Per2 protein expression during warm temperature shifts, but the complete signaling mechanisms are not fully understood.
  • This study identifies eIF2α kinases, specifically PKR and PERK, as new mediators of Per2 expression in response to temperature changes, functioning as upstream regulators of PI3K rather than via eIF2α.

Article Abstract

Temperature-dependent translational control of the core clock gene Per2 plays an important role in establishing entrainment of the circadian clock to physiological body temperature cycles. Previously, we found an involvement of the phosphatidylinositol 3-kinase (PI3K) in causing Per2 protein expression in response to a warm temperature shift (WTS) within a physiological range (from 35 to 38.5 °C). However, signaling pathway mediating the Per2 protein expression in response to WTS is only sparsely understood. Additional factor(s) other than PI3K remains unknown. Here we report the identification of eukaryotic initiation factor 2α (eIF2α) kinases, protein kinase R (PKR) and PKR-like endoplasmic reticulum kinase (PERK), as a novel mediator of WTS-dependent Per2 protein expression. Canonically, eIF2α has been regarded as a major downstream target of PERK and PKR. However, we found that PERK and PKR mediate WTS response of Per2 in a manner not involving eIF2α. We observed that PERK and PKR serve as an upstream regulator of PI3K rather than eIF2α in the context of WTS-dependent Per2 protein expression. There have been studies reporting PI3K activation occurring depending on PERK and PKR, while its physiological contribution has remained elusive. Our finding therefore not only helps to enrich the knowledge of how WTS affects Per2 protein expression but also extends the region of cellular biology involving the PERK/PKR-mediated PI3K activation to include entrainment-mechanism of the circadian clock.

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http://dx.doi.org/10.1248/bpb.b23-00739DOI Listing

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