Discovered: Why do cells age?

Washington: Why do cells age? The biological mystery seems to have been solved, thanks to scientists who`ve discovered a weakness in a component of brain cells which they claim may be responsible for ageing process occurring in mind.

A team at Salk Institute for Biological Studies says that the findings may pave the way for better understanding of diseases like Alzheimer`s and Parkinson`s, the latest edition of the `Science` journal reported.

In the research, the scientists have in fact discovered that certain proteins, called extremely long-lived proteins (ELLPs), found on surface of the nucleus of neurons, have a remarkably long lifespan.

While the lifespan of most proteins totals two days or less, the scientists identified ELLPs in the rat brain that were as old as the organism, they say.

ELLPs make up the transport channels on the surface of the nucleus; gates that control what materials enter and exit.

Damage to the ELLPs weakens the ability of three- dimensional transport channels composed of these proteins to safeguard the cell`s nucleus from toxins, said Prof Martin Hetzer, who led the team.

These toxins may alter the cell`s DNA and thereby the activity of genes, resulting in cellular ageing.

Prof Hetzer added: "The fundamental defining feature of ageing is an overall decline in the functional capacity of various organs such as the heart and the brain. This decline results from deterioration of the homeostasis, or internal stability, within the constituent cells of those organs.

"Recent research has linked breakdown of protein homeostasis to declining cell function. Our results also suggest that nuclear pore deterioration might be a general ageing mechanism leading to age-related defects in nuclear function."