Mitochondria, calcium and pro-apoptotic proteins as mediators in cell death signaling

• Autor(a) principal: Smaili,S.S.
• Data de Publicação: 2003
• Outros Autores: Hsu,Y.-T., Carvalho,A.C.P., Rosenstock,T.R., Sharpe,J.C., Youle,R.J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Medical and Biological Research
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000200004
• topic: Ca2+; Mitochondrial Ca2+ uptake; Mitochondrial Ca2+ efflux; Permeability transition; Apoptosis; Bcl-2 family; Bax and apoptosis

Cellular Ca2+ signals are crucial in the control of most physiological processes, cell injury and programmed cell death through the regulation of a number of Ca2+-dependent enzymes such as phospholipases, proteases, and nucleases. Mitochondria along with the endoplasmic reticulum play pivotal roles in regulating intracellular Ca2+ content. Mitochondria are endowed with multiple Ca2+ transport mechanisms by which they take up and release Ca2+ across their inner membrane. During cellular Ca2+ overload, mitochondria take up cytosolic Ca2+, which in turn induces opening of permeability transition pores and disrupts the mitochondrial membrane potential (<FONT FACE=Symbol>Dy</FONT>m). The collapse of <FONT FACE=Symbol>Dy</FONT>m along with the release of cytochrome c from mitochondria is followed by the activation of caspases, nuclear fragmentation and cell death. Members of the Bcl-2 family are a group of proteins that play important roles in apoptosis regulation. Members of this family appear to differentially regulate intracellular Ca2+ level. Translocation of Bax, an apoptotic signaling protein, from the cytosol to the mitochondrial membrane is another step in this apoptosis signaling pathway.