Deletion of the BH1 domain of Bcl-2 accelerates apoptosis by acting in a dominant negative fashion

Makoto Kawatani, Masaya Imoto

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

To investigate the exact biochemical functions by which Bcl-2 regulates apoptosis, we established a stable human small cell lung carcinoma cell line, Ms-1, overexpressing wild-type human Bcl-2 or various deletion and point mutants thereof, and examined the effect of these Bcl-2 mutants on apoptosis induced by antitumor drugs such as camptothecin. Cytochrome c release, caspase-3(-like) protease activation, and apoptosis induced by antitumor drugs were accelerated by overexpression of Bcl-2 lacking a Bcl-2 homology (BH) 1 domain (Bcl-2/ΔBH1), but not by that of BH2, BH3, or BH4 domain-deleted Bcl-2. A similar result was obtained upon the substitution of glycine 145 with alanine in the BH1 domain (Bcl-2/G145A), which failed to interact with either Bax or Bak. Pro-apoptotic Bax and Bak have been known to be activated in response to antitumor drugs, and Bcl-2/G145A as well as Bcl-2/ΔBH1 also accelerated Bax- or Bak-induced apoptosis in HEK293T cells. These two mutants still retained the ability to interact with wild-type Bcl-2 and Bcl-xL, and abrogated the inhibitory effect of wild-type Bcl-2 or Bcl-xL on Bax- or Bak-induced apoptosis. In addition, immunoprecipitation studies revealed that Bcl-2/ΔBH1 and Bcl-2/G145A interrupted the association between wild-type Bcl-2 and Bax/Bak. Taken together, our results demonstrate that Bcl-2/ΔBH1 or Bcl-2/G145A acts as a dominant negative of endogenous anti-apoptotic proteins such as Bcl-2 and Bcl-xL, thereby enhancing antitumor drug-induced apoptosis, and that this dominant negative activity requires both a failure of interaction with Bax and Bak through the BH1 domain of Bcl-2 and retention of the ability to interact with Bcl-2 and Bcl-xL.

Original languageEnglish
Pages (from-to)19732-19742
Number of pages11
JournalJournal of Biological Chemistry
Volume278
Issue number22
DOIs
Publication statusPublished - 2003 May 30

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Apoptosis
Antineoplastic Agents
Cells
Camptothecin
Apoptosis Regulatory Proteins
Small Cell Lung Carcinoma
Cytochromes c
Immunoprecipitation
Caspase 3
Alanine
Glycine
Peptide Hydrolases
Substitution reactions
Chemical activation
Association reactions
Cell Line

ASJC Scopus subject areas

  • Biochemistry

Cite this

Deletion of the BH1 domain of Bcl-2 accelerates apoptosis by acting in a dominant negative fashion. / Kawatani, Makoto; Imoto, Masaya.

In: Journal of Biological Chemistry, Vol. 278, No. 22, 30.05.2003, p. 19732-19742.

Research output: Contribution to journalArticle

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