A novel human protease similar to the interleukin-1 beta converting enzyme induces apoptosis in transfected cells.

Abstract

We have identified a novel cDNA encoding a protein (named TX) with > 50% overall sequence identity with the interleukin‐1 beta converting enzyme (ICE) and approximately 30% sequence identity with the ICE homologs NEDD‐2/ICH‐1L and CED‐3. A computer homology model of TX was constructed based on the X‐ray coordinates of the ICE crystal recently published. This model suggests that TX is a cysteine protease, with the P1 aspartic acid substrate specificity retained. Transfection experiments demonstrate that TX is a protease which is able to cleave itself and the p30 ICE precursor, but not to generate mature IL‐1 beta from pro‐IL‐1 beta. In addition, this protein induces apoptosis in transfected COS cells. TX therefore delineates a new member of the growing Ice/ced‐3 gene family coding for proteases with cytokine processing activity or involved in programmed cell death.

Involvement of caspase-4(-like) protease in Fas-mediated apoptotic pathway

“…p19 is the amino-terminal cleavage product resulting from cleavage at Asp-9 and indicates that there is no involvement of caspase-1 in Fas-mediated apoptosis of hepatocytes, is consistent with the lack or extremely low levels of caspase-1 mRNA in the liver. Unlike caspase-1, caspase-4 is highly expressed in the liver (not shown; Faucheu et al, 1995;Kamens et al, 1995;Munday et al, 1995), so caspase-4 might be directly involved in Fas-mediated apoptosis of hepatocytes. The observation that the expression of mutant procaspase-4 inhibits the Fas-induced activation of caspase-3(-like) proteases which are essential for Fasmediated apoptosis, strongly suggests that caspase-4 acts at a step leading to the activation of caspase-3, and the in vitro cleavage of pro-caspase-3 by caspase-4 raised the possibility that caspase-4 directly processes pro-caspase-3 in vivo.…”

Affinity labeling displays the stepwise activation of ICE-related proteases by Fas, staurosporine, and CrmA-sensitive caspase-8

“…The N-terminal His-tagged caspases-3, -6/a, and -8 were puri®ed from E. coli extracts by a nity chromatography with Ni 2+ -NTA agarose (Qiagen) according to the manufacturer's instructions. Human caspase-4 (Faucheu et al, 1995;Kamens et al, 1995;Munday et al, 1995) and caspase-7/a (Fernandes- Alnemri et al, 1995b;Duan et al, 1996a;Lippke et al, 1996) were expressed in DH5a E. coli as full-length proteins fused to glutathione-Stransferase at their N-termini. E. coli lysates containing active proteases were prepared as described (FernandesAlnemri et al, 1995a;Takahashi et al, 1996a).…”

“…The cascade hypothesis is mainly based on demonstrations that recombinant caspases-1, 3, 4, 6/a, and 10 can process precursor(s) of other caspase(s) (Faucheu et al, 1995;Fernandes-Alnemri et al, 1995bLiu et al, 1996;Srinivasula et al, 1996). However, most of those data were derived from in vitro experiments using recombinant proteins expressed in bacteria, or from analysis of cells in which caspases were overexpressed.…”

Ligation of CD40 rescues Ramos‐Burkitt lymphoma B cells from calcium ionophore‐ and antigen receptor‐triggered apoptosis by inhibiting activation of the cysteine protease CPP32/Yama and cleavage of its substrate PARP

“…The ICE family is now known to comprise at least five members including CPP32/Yama/apopain [10][11][12], Nedd-2/ ICH-1 [13,14], TX/ICH-2/ICErealI [15][16][17], ICErellII [17] and Mch-2 [18]; Fernandes-Alnemri et al [19] and Duan et al [20] have recently described novel additions to the family, Mch-3 and ICE-LAP3 respectively, which are closely related to CPP32/Yama. All family members to date are synthesised as proenzymes that are proteolytically processed to form active heterodimeric proteases that contain the pentameric peptide, QACRG, which surrounds the putative catalytic residue cysteine [10][11][12][13][14][15][16][17][18][19][20].…”

“…All family members to date are synthesised as proenzymes that are proteolytically processed to form active heterodimeric proteases that contain the pentameric peptide, QACRG, which surrounds the putative catalytic residue cysteine [10][11][12][13][14][15][16][17][18][19][20]. Ectopic expression of ICE and its relatives resuits in the apoptosis of a variety of host cells which can be arrested by the cowpox serpin Crm A or by tetrapeptide (YVAD) inhibitors of ICE-like proteases [14,21,22].…”