Protein involved in longevity `identified`

Updated: May 08, 2010, 00:00 AM IST

Washington: In a major finding which may
have relevance to human biology, scientists have identified a
key protein which is involved in the longevity of roundworms.

A team at Thomas Jefferson University has found that
worms born without this protein, called arrestin, lived about
one-third longer than normal, while worms that had triple the
amount of arrestin lived one-third less.

The research also showed that arrestin interacts with
several other proteins within cells to regulate longevity. The
human version of one of these proteins is PTEN, a well-known
tumor suppressor, the `Biology and Nature` journal reported.

Because most proteins in worms have human
counterparts, these findings may have relevance to human
biology and the understanding of cancer development, said lead
scientist Jeffrey L Benovic.

"The links we have found in worms suggest the same
kind of interactions occur in mammals although human biology
is certainly more complicated. We have much work to do to sort
out these pathways, but that is our goal," said Benovic.

In their research, the scientists used the roundworm
as a model because it offers a simple system to study the
function of genes and proteins that are relevant to human

The worm, for example, has one arrestin gene, whereas
humans have four. Worms only have 302 neurons compared to the
100 billion or so in the human brain. In addition, their short
lifespan of two to three weeks allows for timely observation
of effects on longevity.

The team studied signalling pathways activated by G
protein-coupled receptors. These receptors bind to all kinds
of hormones, sensory stimuli, and neurotransmitters which then
activate a cascade of signals inside the cell.

They regulate many physiological processes and are the
target for about half of the drugs currently on the market.

"When it comes to receptors, worms are actually more
complex. Humans have about 800 different kinds of G protein
-coupled receptors while the worm has about 1,800. It relies
upon these receptors to respond to sensory stimuli as well as
various neurotransmitters and hormones," Benovic said.