terça-feira, 16 de fevereiro de 2010

Apoptose - morte ou ULTRADIFERENCIAÇÃO ?


Para a célula que vai sofrer a apoptose, não há sentido neste suicídio pelo bem coletivo (ver O GENE EGOÍSTA, R. Dawkins), porém se este processo tivesse sido selecionado por outro motivo - diferenciação.

leia a seguir o ABSTRACT:

The benefits of apoptosis for a multicellular organism are obvious and fit the current dogma that the maintenance and viability of such organisms are dependent on the selective elimination of unneeded or deleterious cell types. However, self destruction at the level of the individual cell defies the most basic precepts of biology (sustaining life). If apoptosis is viewed through this construct then one question becomes paramount, i.e., why would an individual cell and its progeny develop, retain, or evolve a mechanism the sole purpose of which is to eliminate itself? In consideration of such a paradox, it is reasonable to postulate that prospective apoptotic pathways coevolved with and or were co-opted from another basic cell function(s) that did not involve the death of the cell per se. In the following article, we present the hypothesis that the conserved biochemical pathways of apoptosis are integral components of terminal cell differentiation and it is the time of engagement and activity level of these pathways that ultimately determines the choice between cell death or cell maturation.


Current Research Activities
Cell Fate Determination
Multi-cellular organisms contain an impressive array of cell phenotypes, a catalogue of almost limitless possibilities. Despite such complexity, basic cell fate is limited in scope. For example, at some point in their respective life cycle, all cells from simple or complex biota will divide, mature, senesce and die. The endpoint for each cell fate appears distinct, yet the initial changes that take place within dividing, dying, or maturing cells are remarkable similar. Our laboratory is exploring the hypothesis that changes in cell fate are initiated by a limited set of core proteins. Moreover, it is our contention that this core set of regulatory factors are widely known pro-apoptotic proteins.

Determinação do destino celular

Organismos multi-celulares apresentam um impressionante conjunto de fenótipos, um catálogo quase ilimitado de possibilidade. A despeito desta complexidade, o destino básico é limitado. Por exemplo, em algum momento nos seus respectivos ciclos de vida, todas as células, em biotas simples ou complexas, irão se dividir, amadurecer, sofrer senescência e morrer. O ponto final de cada célula parece distinto, ainda que as mudanças iniciais que ocorrem em cada etapa é marcantente similar. No laboratório trabalha-se com a hipótese de as mudanças no destino são iniciados por um limitado grupo de proteínas. Além disso, argumentamos que este grupo de fatores de regulação são amplamente conhecidos como proteínas PRO-APOPTÓTICAS.

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