Date of Award
Doctor of Philosophy (PhD)
Biochemistry & Molecular Biophysics
Kelly L. Jordan-Sciutto
PERK is a transmembrane kinase located on the ER with a luminal domain that senses ER stresses, such as protein misfolding, and a cytosolic kinase domain. Upon stress sensing, PERK activates and phosphorylates eIF2α to attenuate global translation while upregulating select transcripts to re-establish protein homeostasis. In a secondary phase of signaling PERK can also induce apoptosis to dispose of terminally stressed and damaged cells. The thus delineated bi-phasic nature of PERK signaling requires tight regulation for homeostatic function, as evidenced by dysregulation of this pathway being implicated in many diseases, including cancers and neurodegenerative conditions. Pursuant attempts to therapeutically modulate PERK and its signaling outcomes have highlighted that our understanding of the determinants of adaptive vs. mal-adaptive signaling remain ambiguous, and further delineation of PERK regulation is required. Here we follow-up on a screen for copper regulated kinases in which PERK was identified as a potential hit. Copper binding activity was confirmed by selective pull-down with copper charged resin and ICP-MS quantification of bound copper. Furthermore a putative binding site identified based on homology copper-binding was determined to be necessary for kinase activity in in vitro kinase assay. PERK-copper binding was also determined to be a physiological method of PERK regulation as manipulations of copper availability in cells were able to modulate PERK activity and signaling. We are now using this relationship to examine how copper can be used to manipulate ER stress tolerance and cell fate outcomes. This novel regulatory mechanism has broad implications for modulating PERK activity in different diseases and disease models, and may constitute a previously unaccounted for variable in determining when PERK inhibition vs. activation is therapeutically beneficial. Our identification of PERK, with its known regulation of and by calcium, as a copper regulated kinase lays the groundwork for future studies evaluating how PERK may itself act as a node of integration and regulation between these two signaling networks, lending vast implications for the role of PERK in physiology and disease, as well as potential elucidation of the mechanisms driving some of the complex biological processes involved.
Bond, Sarah Elizabeth, "Copper A Novel Regulator Of Perk" (2022). Publicly Accessible Penn Dissertations. 5616.