Distress Signal from Injured Nerve Begins with Local Protein

When the longest cells in the body are injured, up to one meter in adult humans needs to be covered in order to reach the cell's nucleus

Injury to the longest cells in the body means coordinating that cells’ repair, and is no easy task. In part because these peripheral nerve cells can be extremely long – up to one meter in adults – which is a lot of distance in order to reach the “command center” of the cell’s nucleus.

Scientists have believed this process to be even more challenging because their textbook understanding for many years has been that the axons – the long extensions of nerve cells away from the main cell body containing the nucleus – do not manufacture the proteins involved in the molecular signal themselves.

Yet, in recent years, some scientists have begun to challenge that textbook understanding, with preliminary evidence that one key protein involved in setting off a distress signal for cell repair, known as importin beta1, was locally produced in the axons. They just weren’t sure how.

“Now these textbooks need to be rewritten. Our new research is one of the strongest indicators yet of molecular signaling from end to end in peripheral nerve cells,” says Dr. Jeffery Twiss, professor and head of the department of biology in Drexel University’s College of Arts and Sciences. Twiss co-authored new research recently published in Neuron, led by collaborators from the Weizmann Institute of Science.

The research has provided strong new evidence that
the protein importin beta1 is indeed produced locally
in the axons of peripheral nerve cells.
They also found that the version of the protein,
when found in the axon, is made using a different
molecular recipe than the version found in the nucleus,
where it performs different essential cell functions.

These discoveries help scientists better understand how subsequent steps operate in the distress signal and in nerve cell repair, so they can eventually control and enhance the process to speed up recovery from nerve injuries.

Original article:
http://www.drexel.edu/now/news-media/releases/archive/2012/July/Injured-Nerve-Axons-Signal-Distress-with-Locally-Made-Protein/