8jns
From Proteopedia
cryo-EM structure of a CED-4 hexamer
Structural highlights
FunctionCED4_CAEEL Isoform a plays a major role in programmed cell death (PCD, apoptosis). Egl-1 binds to and directly inhibits the activity of ced-9, releasing the cell death activator ced-4 from a ced-9/ced-4 containing protein complex and allowing ced-4 to activate the cell-killing caspase ced-3. Isoform b prevents PCD.[1] [2] [3] [4] [5] Publication Abstract from PubMedIn Caenorhabditis elegans (C. elegans), onset of programmed cell death is marked with the activation of CED-3, a process that requires assembly of the CED-4 apoptosome. Activated CED-3 forms a holoenzyme with the CED-4 apoptosome to cleave a wide range of substrates, leading to irreversible cell death. Despite decades of investigations, the underlying mechanism of CED-4-facilitated CED-3 activation remains elusive. Here, we report cryo-EM structures of the CED-4 apoptosome and three distinct CED-4/CED-3 complexes that mimic different activation stages for CED-3. In addition to the previously reported octamer in crystal structures, CED-4, alone or in complex with CED-3, exists in multiple oligomeric states. Supported by biochemical analyses, we show that the conserved CARD-CARD interaction promotes CED-3 activation, and initiation of programmed cell death is regulated by the dynamic organization of the CED-4 apoptosome. Structural insights into CED-3 activation.,Li Y, Tian L, Zhang Y, Shi Y Life Sci Alliance. 2023 Jul 4;6(9):e202302056. doi: 10.26508/lsa.202302056. Print , 2023 Sep. PMID:37402593[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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