Structural highlights
Publication Abstract from PubMedThe endoplasmic reticulum (ER) unfolded protein response (UPR) is comprised of several intracellular signaling pathways that alleviate ER stress. The ER-localized transmembrane kinase PERK is one of three major ER stress transducers. Oligomerization of PERK's N-terminal ER luminal domain by ER stress promotes PERK trans-autophosphorylation of the C-terminal cytoplasmic kinase domain at multiple residues including Thr980 on the kinase activation loop. Activated PERK phosphorylates Ser51 of the alpha-subunit of translation initiation factor 2 (eIF2alpha), which inhibits initiation of protein synthesis and reduces the load of unfolded proteins entering the ER. The crystal structure of PERK's kinase domain has been determined to 2.8 A resolution. The structure resembles the back-to-back dimer observed in the related eIF2alpha kinase PKR. Phosphorylation of Thr980 stabilizes both the activation loop and helix alphaG in the C-terminal lobe, preparing the latter for eIF2alpha binding. The structure suggests conservation in the mode of activation of eIF2alpha kinases and is consistent with a `line-up' model for PERK activation triggered by oligomerization of its luminal domain. The structure of the PERK kinase domain suggests the mechanism for its activation.,Cui W, Li J, Ron D, Sha B Acta Crystallogr D Biol Crystallogr. 2011 May;67(Pt 5):423-8. Epub 2011 Apr 13. PMID:21543844[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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