A Novel BH3-like Domain in BID Is Required for Intramolecular Interaction and Autoinhibition of Pro-apoptotic Activity

Abstract

Upon activation of the Fas apoptotic signaling pathway, Bid, a “BH3 domain-only” pro-apoptotic molecule, is cleaved by caspase-8 into a 6.5-kDa N-terminal and a 15-kDa BH3 domain-containing C-terminal fragment, referred to as tn-Bid and tc-Bid, respectively. tc-Bid is a more potent inducer of apoptosis than full-length Bid, suggesting that the N-terminal region of Bid has an inhibitory effect on its pro-apoptotic activity. Here, we report the identification of a novel BH3-like motif (amino acid residues 35–43) in tn-Bid. Although Bid does not homodimerize, tn-Bid is able to associate avidly with tc-Bid. Site-directed mutagenesis revealed that both the novel BH3-like and BH3 domains are necessary for direct binding between tn-Bid and tc-Bid. While full-length Bid does not associate with tn-Bid, substitution of Leu35, a critical residue in mediating tn-Bid/tc-Bid interaction, with Ala in full-length Bid is sufficient to establish Bid/tn-Bid interaction. Interestingly, the L35A Bid mutant is as effective as tc-Bid in inducing apoptosis and binding Bcl-XL. We propose that the intramolecular interaction involving the BH3-like and BH3 domains serves to regulate the pro-apoptotic potential of Bid. Upon activation of the Fas apoptotic signaling pathway, Bid, a “BH3 domain-only” pro-apoptotic molecule, is cleaved by caspase-8 into a 6.5-kDa N-terminal and a 15-kDa BH3 domain-containing C-terminal fragment, referred to as tn-Bid and tc-Bid, respectively. tc-Bid is a more potent inducer of apoptosis than full-length Bid, suggesting that the N-terminal region of Bid has an inhibitory effect on its pro-apoptotic activity. Here, we report the identification of a novel BH3-like motif (amino acid residues 35–43) in tn-Bid. Although Bid does not homodimerize, tn-Bid is able to associate avidly with tc-Bid. Site-directed mutagenesis revealed that both the novel BH3-like and BH3 domains are necessary for direct binding between tn-Bid and tc-Bid. While full-length Bid does not associate with tn-Bid, substitution of Leu35, a critical residue in mediating tn-Bid/tc-Bid interaction, with Ala in full-length Bid is sufficient to establish Bid/tn-Bid interaction. Interestingly, the L35A Bid mutant is as effective as tc-Bid in inducing apoptosis and binding Bcl-XL. We propose that the intramolecular interaction involving the BH3-like and BH3 domains serves to regulate the pro-apoptotic potential of Bid. glutathione S-transferase phenylmethylsulfonyl fluoride polyacrylamide gel electrophoresis The Bcl-2 family of proteins are important regulators of cell death that can be grouped into subfamilies of pro-survival and pro-apoptotic molecules (1Adams J.M. Cory S. Science. 1998; 281: 1322-1326Crossref PubMed Scopus (4779) Google Scholar, 2Chao D.T. Korsmeyer S.J. Annu. Rev. Immunol. 1998; 16: 395-419Crossref PubMed Scopus (1499) Google Scholar, 3Kelekar A. Thompson C.B. Trends Cell Biol. 1998; 8: 324-330Abstract Full Text Full Text PDF PubMed Scopus (535) Google Scholar). Members of this family are characterized by the presence of several conserved motifs, known as the Bcl-2 homology (BH1–4) domains. Association of a pro-survival with a pro-apoptotic member, such as Bcl-XL with Bak, requires the BH1, BH2, and BH3 domains of Bcl-XL and the BH3 domain of Bak (4Muchmore Thompson C.B. PubMed Scopus Google Scholar, Thompson C.B. Science. PubMed Scopus Google Scholar). to a interaction the BH3 domain in pro-apoptotic molecules is for Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google a of cell death that the BH3 domain has as the “BH3 domain-only” Bid, and of J.M. S. Google Scholar, Thompson C.B. Korsmeyer S.J. Full Text PDF PubMed Scopus Google Scholar, D.T. Korsmeyer S.J. PubMed Scopus Google Scholar, S. 16: PubMed Scopus Google Scholar, A. J.M. Cory S. 1998; PubMed Scopus Google Scholar, Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google with Bcl-2 Bcl-XL and cell death J.M. S. Google Scholar, Thompson C.B. Korsmeyer S.J. Full Text PDF PubMed Scopus Google Scholar, D.T. Korsmeyer S.J. PubMed Scopus Google Scholar, S. 16: PubMed Scopus Google Scholar, A. J.M. Cory S. 1998; PubMed Scopus Google Scholar, Biol. 1998; Full Text Full Text PDF PubMed Scopus Google than the conserved of the BH3 the BH3 molecules in acid suggesting that the of molecules be by signaling to be a of the signaling Korsmeyer S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). is on residues by a that can be by Science. PubMed Scopus Google Scholar, S. Full Text Full Text PDF PubMed Scopus Google Scholar). is and of Bcl-XL Bcl-2 Korsmeyer S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). BH3 Bid, has to be a caspase-8 of the and Fas known as signaling 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). Upon Bid is cleaved by caspase-8 into a 6.5-kDa N-terminal and a 15-kDa BH3 domain-containing C-terminal fragment, referred to as tn-Bid and tc-Bid, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). tc-Bid to Bcl-XL more avidly than full-length Bid and is to be the to the 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). tc-Bid is more potent than full-length Bid in inducing and apoptosis 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). has that the of Bid the pro-apoptotic potential of Bid by the inhibitory and the C-terminal BH3 domain to with on the 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). the of this by the N-terminal region is we report the identification of a novel BH3-like domain in the N-terminal region of Bid that is necessary for mediating interaction between the and of Bid. interaction the novel BH3-like domain to be important for the apoptotic of Bid. We propose that the pro-apoptotic potential of Bid is by an involving intramolecular the of the inhibitory by the N-terminal region of Bid, we the acid of Bid for Interestingly, a of 35–43) to the motif of the BH3 domain the tn-Bid The BH3-like referred to as both and several BH3 the BH3 domain in tc-Bid the of the conserved acid the BH3-like motif with BH3 the BH3 domain is known to as a interaction we the of the N-terminal region of Bid that the novel BH3-like motif to with the C-terminal tn-Bid to associate with in tc-Bid not Interestingly, tn-Bid to associate with in full-length Bid the that the region of Bid for interaction with tn-Bid The of tn-Bid with tc-Bid in in in tn-Bid with tc-Bid, not with Bid, with the in tn-Bid to with tc-Bid, not Bcl-XL The of tn-Bid/tc-Bid interaction in the to be to the interaction between Bcl-XL and with tc-Bid in and in in of proteins with proteins as The gel with to the of the of proteins in in binding in Cell the N-terminal and proteins to with the proteins on with the of of by to the of of the and proteins interaction of tn-Bid and tc-Bid in the tn-Bid with tc-Bid into for in of interaction as and binding the in the tn-Bid and tc-Bid are the BH3-like and BH3 domains and several conserved residues of BH3 domains to be necessary for interaction with Bcl-2 Bcl-XL in pro-apoptotic molecules Thompson C.B. Science. PubMed Scopus Google Scholar, D.T. Korsmeyer S.J. PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Biol. 16: PubMed Scopus Google we to the of conserved residues of the BH3 domains in mediating interaction between the tn-Bid and tc-Bid by of the with in Bid D.T. Korsmeyer S.J. PubMed Scopus Google tc-Bid to be sufficient to interaction of molecules with Bcl-XL not The to tn-Bid in the and and suggesting in the BH3 domain of tc-Bid is for interaction with both tn-Bid and Bcl-XL. of several conserved the motif of the BH3 domain to be effective in its A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. 16: PubMed Scopus Google Scholar). the BH3 domain of tc-Bid by acid residues the the binding of tc-Bid to tn-Bid and the of the BH3 domain of tc-Bid in mediating interaction with of the BH3 and domains of of the BH3 and BH3-like domains of Bid. The in the of Bid, tn-Bid, tc-Bid by interaction of tn-Bid, tc-Bid, and in the tn-Bid tn-Bid with tc-Bid tc-Bid into for in of interaction as and binding and in binding of tc-Bid tc-Bid with proteins of tn-Bid tn-Bid as The with to that of the proteins in residue in the BH3 domain of Bid is BH3 domains in the domain of both and Bid, the is by and of the to the in tn-Bid effect on the of interaction between and tc-Bid and a of the conserved acid in the BH3 domain of tc-Bid to the the to the binding of tc-Bid to tn-Bid and that the acid the of the conserved acid has in tn-Bid/tc-Bid interaction. The of the conserved residue of BH3 domains in pro-apoptotic molecules for mediating interaction with Bcl-XL has not While the BH3 domain-containing of Bak the of the conserved acid for mediating interaction with Bcl-XL Thompson C.B. Science. PubMed Scopus Google and the of acid residues in the BH3 domain of to a of the conserved residue for with Bcl-XL A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). is that the conserved residue does not the in BH3 domain-containing pro-apoptotic to the of the BH3 domain in tc-Bid, substitution of the conserved to in the domain of tn-Bid effect on the binding of tn-Bid to tc-Bid and suggesting that the conserved in the domain of tn-Bid is not for interaction with tc-Bid. of the conserved of the BH3 domain to Ala in is sufficient to with Bcl-XL Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). of the conserved in tn-Bid to L35A its to associate with tc-Bid and While the and the of tn-Bid not the binding of tn-Bid to tc-Bid, substitution of residues the region of BH3 to in tn-Bid its to tc-Bid and that the conserved acid residues of the novel BH3-like domain are critical in mediating interaction between the tn-Bid and with tc-Bid, not full-length Bid, suggesting that intramolecular interaction in Bid be for with tn-Bid. this is such as L35A and in tn-Bid that interaction of tn-Bid with tc-Bid are to a effect in Bid, in of the intramolecular interaction of Bid and the to with tn-Bid. this we L35A and into the domain of full-length Bid and the of to with in the L35A and Bid not the Bid, Bid, Bid, able to associate with tn-Bid with the that Bid does not D.T. Korsmeyer S.J. PubMed Scopus Google a in the and of Bid novel domain in Bid is for intramolecular interaction and of pro-apoptotic of Bid. tn-Bid to L35A and Bid not Bid. Bid and in and with gel the of in binding is in the domain of Bid its apoptotic to that of tc-Bid. with of the and of as The are of as a of of of for and Bcl-XL the apoptotic of tc-Bid more than tn-Bid. tc-Bid with the of with to as in Bcl-XL to L35A and Bid more than to Bid. with in Bid and Bid and to as in the of in binding the that the intramolecular interaction of Bid as an to regulate the pro-apoptotic of Bid. apoptosis tn-Bid is tc-Bid is more potent than Bid in inducing cell death as 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google to the Bid, the Bid mutant that to tn-Bid apoptotic the apoptotic of both the L35A and the Bid to a to the tc-Bid that the intramolecular interaction between the and of Bid its apoptotic activity. in for tc-Bid to its potent apoptotic effect in to the tn-Bid with tc-Bid to its apoptotic the apoptotic of tc-Bid not by tn-Bid, by Bcl-XL is not as the N-terminal region of Bid not be effective in its to with the apoptotic of binding of tc-Bid to Bcl-XL is to be a by Bid its apoptotic effect by be of to the of N-terminal region of Bid in Bid binding to Bcl-XL. We the binding of Bid, tc-Bid, and Bid to Bcl-XL. Interestingly, Bid and the Bid and that to intramolecular interaction with the Bid and that to the to to as as tc-Bid to Bcl-XL with in not to a in the N-terminal region serves to regulate the apoptotic of Bid by the of the C-terminal domain with the in the of Bid Full Text Full Text PDF PubMed Scopus Google Scholar, J.M. Korsmeyer S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). Bid in such a that are by of the and are in tn-Bid. The motif of the Full Text Full Text PDF PubMed Scopus Google Scholar). the of the by its in mediating direct with the The Bcl-2 family of proteins are important regulators of cell death that can be grouped into subfamilies of pro-survival and pro-apoptotic molecules (1Adams J.M. Cory S. Science. 1998; 281: 1322-1326Crossref PubMed Scopus (4779) Google Scholar, 2Chao D.T. Korsmeyer S.J. Annu. Rev. Immunol. 1998; 16: 395-419Crossref PubMed Scopus (1499) Google Scholar, 3Kelekar A. Thompson C.B. Trends Cell Biol. 1998; 8: 324-330Abstract Full Text Full Text PDF PubMed Scopus (535) Google Scholar). Members of this family are characterized by the presence of several conserved motifs, known as the Bcl-2 homology (BH1–4) domains. Association of a pro-survival with a pro-apoptotic member, such as Bcl-XL with Bak, requires the BH1, BH2, and BH3 domains of Bcl-XL and the BH3 domain of Bak (4Muchmore Thompson C.B. PubMed Scopus Google Scholar, Thompson C.B. Science. PubMed Scopus Google Scholar). to a interaction the BH3 domain in pro-apoptotic molecules is for Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). a of cell death that the BH3 domain has as the “BH3 domain-only” Bid, and of J.M. S. Google Scholar, Thompson C.B. Korsmeyer S.J. Full Text PDF PubMed Scopus Google Scholar, D.T. Korsmeyer S.J. PubMed Scopus Google Scholar, S. 16: PubMed Scopus Google Scholar, A. J.M. Cory S. 1998; PubMed Scopus Google Scholar, Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google with Bcl-2 Bcl-XL and cell death J.M. S. Google Scholar, Thompson C.B. Korsmeyer S.J. Full Text PDF PubMed Scopus Google Scholar, D.T. Korsmeyer S.J. PubMed Scopus Google Scholar, S. 16: PubMed Scopus Google Scholar, A. J.M. Cory S. 1998; PubMed Scopus Google Scholar, Biol. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). than the conserved of the BH3 the BH3 molecules in acid suggesting that the of molecules be by signaling to be a of the signaling Korsmeyer S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). is on residues by a that can be by Science. PubMed Scopus Google Scholar, S. Full Text Full Text PDF PubMed Scopus Google Scholar). is and of Bcl-XL Bcl-2 Korsmeyer S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). BH3 Bid, has to be a caspase-8 of the and Fas known as signaling 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). Upon Bid is cleaved by caspase-8 into a 6.5-kDa N-terminal and a 15-kDa BH3 domain-containing C-terminal fragment, referred to as tn-Bid and tc-Bid, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). tc-Bid to Bcl-XL more avidly than full-length Bid and is to be the to the 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). tc-Bid is more potent than full-length Bid in inducing and apoptosis 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). has that the of Bid the pro-apoptotic potential of Bid by the inhibitory and the C-terminal BH3 domain to with on the 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). the of this by the N-terminal region is we report the identification of a novel BH3-like domain in the N-terminal region of Bid that is necessary for mediating interaction between the and of Bid. interaction the novel BH3-like domain to be important for the apoptotic of Bid. We propose that the pro-apoptotic potential of Bid is by an involving intramolecular interaction. the of the inhibitory by the N-terminal region of Bid, we the acid of Bid for Interestingly, a of 35–43) to the motif of the BH3 domain the tn-Bid The BH3-like referred to as both and several BH3 the BH3 domain in tc-Bid the of the conserved acid the BH3-like motif with BH3 the BH3 domain is known to as a interaction we the of the N-terminal region of Bid that the novel BH3-like motif to with the C-terminal tn-Bid to associate with in tc-Bid not Interestingly, tn-Bid to associate with in full-length Bid the that the region of Bid for interaction with tn-Bid The of tn-Bid with tc-Bid in in in tn-Bid with tc-Bid, not with Bid, with the in tn-Bid to with tc-Bid, not Bcl-XL The of tn-Bid/tc-Bid interaction in the to be to the interaction between Bcl-XL and the in the tn-Bid and tc-Bid are the BH3-like and BH3 domains and several conserved residues of BH3 domains to be necessary for interaction with Bcl-2 Bcl-XL in pro-apoptotic molecules Thompson C.B. Science. PubMed Scopus Google Scholar, D.T. Korsmeyer S.J. PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Biol. 16: PubMed Scopus Google we to the of conserved residues of the BH3 domains in mediating interaction between the tn-Bid and tc-Bid by of the with in Bid D.T. Korsmeyer S.J. PubMed Scopus Google tc-Bid to be sufficient to interaction of molecules with Bcl-XL not The to tn-Bid in the and and suggesting in the BH3 domain of tc-Bid is for interaction with both tn-Bid and Bcl-XL. of several conserved the motif of the BH3 domain to be effective in its A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. 16: PubMed Scopus Google Scholar). the BH3 domain of tc-Bid by acid residues the the binding of tc-Bid to tn-Bid and the of the BH3 domain of tc-Bid in mediating interaction with of the BH3 and domains of of the BH3 and BH3-like domains of Bid. The in the of Bid, tn-Bid, tc-Bid by interaction of tn-Bid, tc-Bid, and in the tn-Bid tn-Bid with tc-Bid tc-Bid into for in of interaction as and binding and in binding of tc-Bid tc-Bid with proteins of tn-Bid tn-Bid as The with to that of the proteins in residue in the BH3 domain of Bid is BH3 domains in the domain of both and Bid, the is by and of the to the in tn-Bid effect on the of interaction between and tc-Bid and a of the conserved acid in the BH3 domain of tc-Bid to the the to the binding of tc-Bid to tn-Bid and that the acid the of the conserved acid has in tn-Bid/tc-Bid interaction. The of the conserved residue of BH3 domains in pro-apoptotic molecules for mediating interaction with Bcl-XL has not While the BH3 domain-containing of Bak the of the conserved acid for mediating interaction with Bcl-XL Thompson C.B. Science. PubMed Scopus Google and the of acid residues in the BH3 domain of to a of the conserved residue for with Bcl-XL A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). is that the conserved residue does not the in BH3 domain-containing pro-apoptotic to the of the BH3 domain in tc-Bid, substitution of the conserved to in the domain of tn-Bid effect on the binding of tn-Bid to tc-Bid and suggesting that the conserved in the domain of tn-Bid is not for interaction with tc-Bid. of the conserved of the BH3 domain to Ala in is sufficient to with Bcl-XL Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). of the conserved in tn-Bid to L35A its to associate with tc-Bid and While the and the of tn-Bid not the binding of tn-Bid to tc-Bid, substitution of residues the region of BH3 to in tn-Bid its to tc-Bid and that the conserved acid residues of the novel BH3-like domain are critical in mediating interaction between the tn-Bid and with tc-Bid, not full-length Bid, suggesting that intramolecular interaction in Bid be for with tn-Bid. this is such as L35A and in tn-Bid that interaction of tn-Bid with tc-Bid are to a effect in Bid, in of the intramolecular interaction of Bid and the to with tn-Bid. this we L35A and into the domain of full-length Bid and the of to with in the L35A and Bid not the Bid, Bid, Bid, able to associate with tn-Bid with the that Bid does not D.T. Korsmeyer S.J. PubMed Scopus Google a in the and of Bid novel domain in Bid is for intramolecular interaction and of pro-apoptotic of Bid. tn-Bid to L35A and Bid not Bid. Bid and in and with gel the of in binding is in the domain of Bid its apoptotic to that of tc-Bid. with of the and of as The are of as a of of of for and Bcl-XL the apoptotic of tc-Bid more than tn-Bid. tc-Bid with the of with to as in Bcl-XL to L35A and Bid more than to Bid. with in Bid and Bid and to as in the of in binding the that the intramolecular interaction of Bid as an to regulate the pro-apoptotic of Bid. apoptosis tn-Bid is tc-Bid is more potent than Bid in inducing cell death as 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google to the Bid, the Bid mutant that to tn-Bid apoptotic the apoptotic of both the L35A and the Bid to a to the tc-Bid that the intramolecular interaction between the and of Bid its apoptotic activity. in for tc-Bid to its potent apoptotic effect in to the tn-Bid with tc-Bid to its apoptotic the apoptotic of tc-Bid not by tn-Bid, by Bcl-XL is not as the N-terminal region of Bid not be effective in its to with the apoptotic of binding of tc-Bid to Bcl-XL is to be a by Bid its apoptotic effect by be of to the of N-terminal region of Bid in Bid binding to Bcl-XL. We the binding of Bid, tc-Bid, and Bid to Bcl-XL. Interestingly, Bid and the Bid and that to intramolecular interaction with the Bid and that to the to to as as tc-Bid to Bcl-XL with in not to a in the N-terminal region serves to regulate the apoptotic of Bid by the of the C-terminal domain with the in the of Bid Full Text Full Text PDF PubMed Scopus Google Scholar, J.M. Korsmeyer S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). Bid in such a that are by of the and are in tn-Bid. The motif of the Full Text Full Text PDF PubMed Scopus Google Scholar). the of the by its in mediating direct with the the of the inhibitory by the N-terminal region of Bid, we the acid of Bid for Interestingly, a of 35–43) to the motif of the BH3 domain the tn-Bid The BH3-like referred to as both and several BH3 the BH3 domain in tc-Bid the of the conserved acid the BH3-like motif with BH3 domains. the BH3 domain is known to as a interaction we the of the N-terminal region of Bid that the novel BH3-like motif to with the C-terminal tn-Bid to associate with in tc-Bid not Interestingly, tn-Bid to associate with in full-length Bid the that the region of Bid for interaction with tn-Bid The of tn-Bid with tc-Bid in in in tn-Bid with tc-Bid, not with Bid, with the in tn-Bid to with tc-Bid, not Bcl-XL The of tn-Bid/tc-Bid interaction in the to be to the interaction between Bcl-XL and the in the tn-Bid and tc-Bid are the BH3-like and BH3 domains and several conserved residues of BH3 domains to be necessary for interaction with Bcl-2 Bcl-XL in pro-apoptotic molecules Thompson C.B. Science. PubMed Scopus Google Scholar, D.T. Korsmeyer S.J. PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar, Biol. 16: PubMed Scopus Google we to the of conserved residues of the BH3 domains in mediating interaction between the tn-Bid and tc-Bid by of the with in Bid D.T. Korsmeyer S.J. PubMed Scopus Google tc-Bid to be sufficient to interaction of molecules with Bcl-XL not The to tn-Bid in the and and suggesting in the BH3 domain of tc-Bid is for interaction with both tn-Bid and Bcl-XL. of several conserved the motif of the BH3 domain to be effective in its A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. 16: PubMed Scopus Google Scholar). the BH3 domain of tc-Bid by acid residues the the binding of tc-Bid to tn-Bid and the of the BH3 domain of tc-Bid in mediating interaction with tn-Bid. The residue in the BH3 domain of Bid is BH3 domains in the domain of both and Bid, the is by and of the to the in tn-Bid effect on the of interaction between and tc-Bid and a of the conserved acid in the BH3 domain of tc-Bid to the the to the binding of tc-Bid to tn-Bid and that the acid the of the conserved acid has in tn-Bid/tc-Bid interaction. The of the conserved residue of BH3 domains in pro-apoptotic molecules for mediating interaction with Bcl-XL has not While the BH3 domain-containing of Bak the of the conserved acid for mediating interaction with Bcl-XL Thompson C.B. Science. PubMed Scopus Google and the of acid residues in the BH3 domain of to a of the conserved residue for with Bcl-XL A. Korsmeyer S.J. Biol. 1998; PubMed Scopus Google Scholar, Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). is that the conserved residue does not the in BH3 domain-containing pro-apoptotic to the of the BH3 domain in tc-Bid, substitution of the conserved to in the domain of tn-Bid effect on the binding of tn-Bid to tc-Bid and suggesting that the conserved in the domain of tn-Bid is not for interaction with tc-Bid. of the conserved of the BH3 domain to Ala in is sufficient to with Bcl-XL Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google Scholar). of the conserved in tn-Bid to L35A its to associate with tc-Bid and While the and the of tn-Bid not the binding of tn-Bid to tc-Bid, substitution of residues the region of BH3 to in tn-Bid its to tc-Bid and that the conserved acid residues of the novel BH3-like domain are critical in mediating interaction between the tn-Bid and tc-Bid. tn-Bid with tc-Bid, not full-length Bid, suggesting that intramolecular interaction in Bid be for with tn-Bid. this is such as L35A and in tn-Bid that interaction of tn-Bid with tc-Bid are to a effect in Bid, in of the intramolecular interaction of Bid and the to with tn-Bid. this we L35A and into the domain of full-length Bid and the of to with in the L35A and Bid not the Bid, Bid, Bid, able to associate with tn-Bid with the that Bid does not D.T. Korsmeyer S.J. PubMed Scopus Google a in the and of Bid We the that the intramolecular interaction of Bid as an to regulate the pro-apoptotic of Bid. apoptosis tn-Bid is tc-Bid is more potent than Bid in inducing cell death as 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Korsmeyer S.J. Biol. Full Text Full Text PDF PubMed Scopus Google to the Bid, the Bid mutant that to tn-Bid apoptotic the apoptotic of both the L35A and the Bid to a to the tc-Bid that the intramolecular interaction between the and of Bid its apoptotic activity. in for tc-Bid to its potent apoptotic effect in to the tn-Bid with tc-Bid to its apoptotic the apoptotic of tc-Bid not by tn-Bid, by Bcl-XL is not as the N-terminal region of Bid not be effective in its to with the apoptotic of tc-Bid. binding of tc-Bid to Bcl-XL is to be a by Bid its apoptotic effect by be of to the of N-terminal region of Bid in Bid binding to Bcl-XL. We the binding of Bid, tc-Bid, and Bid to Bcl-XL. Interestingly, Bid and the Bid and that to intramolecular interaction with the Bid and that to the to to as as tc-Bid to Bcl-XL with in not to a in the N-terminal region serves to regulate the apoptotic of Bid by the of the C-terminal domain with Bcl-XL. While the in the of Bid Full Text Full Text PDF PubMed Scopus Google Scholar, J.M. Korsmeyer S.J. Full Text Full Text PDF PubMed Scopus Google Scholar). Bid in such a that are by of the and are in tn-Bid. The motif of the Full Text Full Text PDF PubMed Scopus Google Scholar). the of the by its in mediating direct with the We are to and for of the in this We and for critical of the