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3h11

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Zymogen caspase-8:c-FLIPL protease domain complex

Structural highlights

3h11 is a 3 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.9Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CFLAR_HUMAN Apoptosis regulator protein which may function as a crucial link between cell survival and cell death pathways in mammalian cells. Acts as an inhibitor of TNFRSF6 mediated apoptosis. A proteolytic fragment (p43) is likely retained in the death-inducing signaling complex (DISC) thereby blocking further recruitment and processing of caspase-8 at the complex. Full length and shorter isoforms have been shown either to induce apoptosis or to reduce TNFRSF-triggered apoptosis. Lacks enzymatic (caspase) activity.^[1]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Cellular FLICE-inhibitory protein (c-FLIP(L)) is a key regulator of the extrinsic cell death pathway. Although widely regarded as an inhibitor of initiator caspase activation and cell death, c-FLIP(L) is also capable of enhancing procaspase-8 activation through heterodimerization of their respective protease domains. However, the underlying mechanism of this activation process remains enigmatic. Here, we demonstrate that cleavage of the intersubunit linker of c-FLIP(L) by procaspase-8 potentiates the activation process by enhancing heterodimerization between the two proteins and vastly improving the proteolytic activity of unprocessed caspase-(C)8. The crystal structures of the protease-like domain of c-FLIP(L) alone and in complex with zymogen C8 identify the unique determinants that favor heterodimerization over procaspase-8 homodimerization, and induce the latent active site of zymogen C8 into a productive conformation. Together, these findings provide molecular insights into a key aspect of c-FLIP(L) function that modulates procaspase-8 activation to elicit diverse responses in different cellular contexts.

Mechanism of procaspase-8 activation by c-FLIPL.,Yu JW, Jeffrey PD, Shi Y Proc Natl Acad Sci U S A. 2009 May 4. PMID:19416807^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Scaffidi C, Schmitz I, Krammer PH, Peter ME. The role of c-FLIP in modulation of CD95-induced apoptosis. J Biol Chem. 1999 Jan 15;274(3):1541-8. PMID:9880531
↑ Yu JW, Jeffrey PD, Shi Y. Mechanism of procaspase-8 activation by c-FLIPL. Proc Natl Acad Sci U S A. 2009 May 4. PMID:19416807