The three-dimensional structure of caspase-8: an initiator enzyme in apoptosis

Blanchard, Helen; Kodandapani, Lalitha; Mittl, Peer R. E.; Marco, Stefania Di; Krebs, Joseph F.; Wu, Joe C.; Tomaselli, Kevin J.; Grütter, Markus G.

doi:10.1016/s0969-2126(99)80179-8

Cited by 136 publications

(131 citation statements)

References 38 publications

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“…The core of the enzyme is formed by a 12-stranded ␤-sheet, which is surrounded by a total of 14 ␣-helices. The overall fold of caspase-2 is similar to that of other caspases for which structures have been determined previously (30,(32)(33)(34)(35)(36)(37)(38)(39). This is illustrated by a superposition of the C␣ chains with caspase-3, another representative of the specificity group II caspases, and caspase-9, the closest relative of caspase-2 based on sequence identity (Fig.…”

Section: Resultssupporting

confidence: 69%

Crystal Structure of Caspase-2, Apical Initiator of the Intrinsic Apoptotic Pathway

Schweizer

Briand

Grütter

2003

Journal of Biological Chemistry

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The cell death protease caspase-2 has recently been recognized as the most apical caspase in the apoptotic cascade ignited during cell stress signaling. Cytotoxic stress, such as that caused by cancer therapies, leads to activation of caspase-2, which acts as a direct effector of the mitochondrion-dependent apoptotic pathway resulting in programmed cell death. Here we report the x-ray structure of caspase-2 in complex with the inhibitor acetyl-Leu-Asp-Glu-Ser-Asp-aldehyde at 1.65-Å resolution. Compared with other caspases, significant structural differences prevail in the active site region and the dimer interface. The structure reveals the hydrophobic properties of the S5 specificity pocket, which is unique to caspase-2, and provides the details of the inhibitorprotein interactions in subsites S1-S4. These features form the basis of caspase-2 specificity and allow the design of caspase-2-directed ligands for medical and analytical use. Another unique feature of caspase-2 is a disulfide bridge at the dimer interface, which covalently links the two monomers. Consistent with this finding, caspase-2 exists as a (p19/p12) 2 dimer in solution, even in the absence of substrates or inhibitors. The intersubunit disulfide bridge stabilizes the dimeric form of caspase-2, whereas all other long prodomain caspases exist as monomers in solution, and dimer formation is driven by ligand binding. Therefore, the central disulfide bridge appears to represent a novel way of dimer stabilization in caspases.

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Section: Resultssupporting

confidence: 69%

Crystal Structure of Caspase-2, Apical Initiator of the Intrinsic Apoptotic Pathway

Schweizer

Briand

Grütter

2003

Journal of Biological Chemistry

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“…From a mechanistic viewpoint, although both single-chain and two-chain forms of caspase-8 are kinetically equivalent for sodium citrate activation via a bimolecular event, the degree of stability of the cleaved dimer is substantially higher than that of the single-chain dimer (8). Presumably, the single-chain dimer contains fewer contacts in the loop bundle that defines part of the dimer interface produced by interactions with the cleaved interchain linker (8,45). In our dimerizing conditions, k cat was higher and K m was lower for the two-chain form as compared with the single-chain form indicating that sodium citrate facilitates a more efficient attack on the substrate and a better recognition of the substrate in the case of the two-chain caspase-8 (see Table 1 and Fig.…”

Section: Discussionmentioning

confidence: 99%

Cathepsin D Primes Caspase-8 Activation by Multiple Intra-chain Proteolysis

Conus

Pop

Snipas

et al. 2012

Journal of Biological Chemistry

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Background:The exact mechanism of caspase-8 activation by cathepsin D remains unclear. Results: The generation of an active caspase-8 requires both cathepsin D-mediated proteolysis and homodimerization of caspase-8. Conclusion: Cathepsin D is able to directly activate caspase-8. Significance: Cathepsin D-induced caspase-8 activation may represent a general mechanism to induce apoptosis in the absence of death receptor activation in a variety of immune and nonimmune cells.

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“…The recently determined solution structure of procaspase-8 and the available crystal structures of caspase-8 in the presence of various inhibitors provide important information to decipher the activation mechanism of caspase-8. [22][23][24][25] Additional mutational studies dissected the interplay between dimerization and proteolytic cleavage. [13][14][15]22,[26][27][28] Although dimerization is required and by itself sufficient for caspase-8 activity, cleavage of the inter-subunit linker at two different recognition motifs is important for dimer stabilization and is, thus, essential for caspase-8 activity.…”

mentioning

confidence: 99%

Studies of the molecular mechanism of caspase-8 activation by solution NMR

2009

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Caspases are the key players of apoptosis and inflammation. They are present in the cells as latent precursors, procaspases, and are activated upon an apoptotic or inflammatory stimulus. The activation mechanism of caspases has been studied extensively by biochemical and biophysical methods. Additional structural information on active caspases with a variety of different inhibitors bound at the active site is available. In this study, we investigated the cleavage mechanism of caspase-8 from its zymogen to active caspase-8 by solution NMR and by biochemical methods. The intermolecular cleavage reaction using the catalytically inactive C285A procaspase-8 mutant is triggered by adding caspase-8 and followed by 15 N, 1 H-NMR spectroscopy. The spectrum that initially resembles the one of procaspase-8 gradually over time changes to that of caspase-8, and disappearing peaks display exponential decaying intensities. Removal of either one of the cleavage recognition motifs in the linker, or phosphorylation at Tyr380, is shown to reduce the rate of the cleavage reaction. The data suggest that dimerization repositions the linker to become suitable for intermolecular processing by the associated protomer. Furthermore, analysis of inhibitor binding to the active caspase-8 reveals an induced-fit mechanism for substrate binding.

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The three-dimensional structure of caspase-8: an initiator enzyme in apoptosis

Cited by 136 publications

References 38 publications

Crystal Structure of Caspase-2, Apical Initiator of the Intrinsic Apoptotic Pathway

Crystal Structure of Caspase-2, Apical Initiator of the Intrinsic Apoptotic Pathway

Cathepsin D Primes Caspase-8 Activation by Multiple Intra-chain Proteolysis

Studies of the molecular mechanism of caspase-8 activation by solution NMR

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