RESUMO
The execution phase of apoptosis is characterized by marked changes in cell morphology that include contraction and membrane blebbing. Little is known about the mechanisms underlying this process. We report here the identification of a novel member of BNIPL family, designated Bcl-2/adenovirus E1B 19kDa interacting protein 2 like-2 (BNIPL-2), which interacts with Bcl-2 and Cdc42GAP. We found that the human BNIPL-2 shares homology to human BNIP-2 and also possesses a BNIP-2 and Cdc42GAP homology (BCH) domain. Deletion experiments indicated that the BCH domain of BNIPL-2 is critical for its interactions with the Bcl-2 and Cdc42GAP and also for its cell death-inducing function. Our data showed that BNIPL-2 may be a linker protein located at the front end of Bcl-2 pathway for DNA fragmentation and Cdc42 signaling for morphological changes during apoptosis. We propose that BNIPL-2 protein may play an important role in regulation of both pathways for DNA fragmentation and for formation of membrane blebs in apoptotic cells.
Assuntos
Apoptose/fisiologia , Proteínas de Transporte/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Sequência de Bases , Proteínas de Transporte/química , Proteínas de Transporte/genética , DNA Complementar/genética , Humanos , Técnicas In Vitro , Dados de Sequência Molecular , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Deleção de SequênciaRESUMO
A large-scale assay was performed by transfecting 29,910 individual cDNA clones derived from human placenta, fetus, and normal liver tissues into human hepatoma cells and 22,926 cDNA clones into mouse NIH 3T3 cells. Based on the results of colony formation in hepatoma cells and foci formation in NIH 3T3 cells, 3,806 cDNA species (8,237 clones) were found to possess the ability of either stimulating or inhibiting cell growth. Among them, 2,836 (6,958 clones) were known genes, 372 (384 clones) were previously unrecognized genes, and 598 (895 clones) were unigenes of uncharacterized structure and function. A comprehensive analysis of the genes and the potential mechanisms for their involvement in the regulation of cell growth is provided. The genes were classified into four categories: I, genes related to the basic cellular mechanism for growth and survival; II, genes related to the cellular microenvironment; III, genes related to host-cell systemic regulation; and IV, genes of miscellaneous function. The extensive growth-regulatory activity of genes with such highly diversified functions suggests that cancer may be related to multiple levels of cellular and systemic controls. The present assay provides a direct genomewide functional screening method. It offers a better understanding of the basic machinery of oncogenesis, including previously undescribed systemic regulatory mechanisms, and also provides a tool for gene discovery with potential clinical applications.