TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*1.A.21.1.1









Apoptosis regulator Bcl-X(L) of 233 aas.  Also called Bcl2-like protein 1, isoform 1. Membrane insertion of the soluble form has been characterized (Vargas-Uribe et al. 2013).  The cytosolic domain of Bcl-2 forms small pores in the mitochondrial outer membrane (Peng et al. 2009).

Eukaryota
Metazoa
Bcl-X(L) of Homo sapiens
*1.A.21.1.2









The mitochondrial apoptosis-inducing channel-forming protein, BAX.  The C-terminal helix mediates membrane binding and pore formation (Garg et al. 2012). BAX pores are large enough to allow cytochrome c release and it activates the mitochondrial permeabilty transition pore; both play a role in programmed cell death, but the latter is quantitatively more important (Gómez-Crisóstomo et al. 2013). Bax functions like a holin when expressed in bacteria (Pang et al. 2011).  Bax (and likely Bak) dimers assemble into oligomers with an even number of molecules that fully or partially delineate pores of different sizes to permeabilize the mitochondrial outer membrane (MOM) during apoptosis (Cosentino and García-Sáez 2016). The membrane domain of Bax interacts with other members of the Bcl-2 family to form hetero-oligomers (Andreu-Fernández et al. 2017).

Eukaryota
Metazoa
BAX of Homo sapiens (Q07812)
*1.A.21.1.3









The mitochondrial apoptosis-inducing channel-forming protein, BAK. 3-D structures are known (2IMT_A).  Functions like a holin when expressed in bacteria (Pang et al. 2011).  Formation of the apoptotic pore involves a flexible C-terminal domain (Iyer et al. 2015). Bax (and likely Bak) dimers assemble into oligomers with an even number of molecules that fully or partially delineate pores of different sizes to permeabilize the mitochondrial outer membrane (MOM) during apoptosis (Cosentino and García-Sáez 2016). BAK is a C-tail-anchored mitochondrial outer membrane protein (Setoguchi et al. 2006). BAK plays a role in peroxisomal permeability, similar to mitochondrial outer membrane permeabilization (Hosoi et al. 2017).

Eukaryota
Metazoa
BAK of Homo sapiens (Q16611). 
*1.A.21.1.4









The BH3-only (Mcl-1) protein (mediates apoptosis). (3-d strucure known)

Eukaryota
Metazoa
BH3-only of Homo sapiens (B4DG83)
*1.A.21.1.5









Pro-survival Bcl-w protein.  Binds the BH3-only protein Bop to inhibit Bop-induced apoptosis (Zhang et al. 2012).  The structure is known (PDB# 1MK3).

Eukaryota
Metazoa
Bcl-w of Homo sapiens
*1.A.21.1.6









Bcl-XL of 289 aas, a C-tail-anchored mitochondrial outer membrane protein (Setoguchi et al. 2006). The BH4 domain of Bcl-XL, but not that of Bcl-2, selectively targets VDAC1 and inhibits apoptosis by decreasing VDAC1-mediated Ca2+ uptake into mitochondria (Monaco et al. 2015). The ER-mitochondrion interface is a critical cell-signaling junction whereby Bcl-xL dynamically interacts with type 3 inositol 1,4,5-trisphosphate receptors (IP3R3) to coordinate mitochondrial Ca2+ transfer and alters cellular metabolism in order to increase the cells' bioenergetic capacity, particularly during periods of stress (Williams et al. 2016).

Eukaryota
Metazoa
Bcl-XL of Xenopus laevis (African clawed frog)
*1.A.21.2.1









The Cell Death (CED-9) protein (Siskind et al., 2008)
Eukaryota
Metazoa
CED-9 of Caenorhabditis elegans (P41958)