Heat shock proteins are known to protect all cell types from various general assaults. They were originally discovered when cultured cells that were heated expressed the proteins at high levels and proved more resistant to other injuries and toxins. They help fold proteins that are misfolded in times of crisis, help maintain structural integrity of the cell, and serve as a counterbalance to apoptosis. But their specific role in the nervous system is not well known. Now a new study led by Clifford Woolf, the Richard J. Kitz professor of anesthesia research at Massachusetts General Hospital, suggests that a small heat shock protein, Hsp27, helps determine whether injured sensory and motor neurons live or die. The study, published in the Sept. 26, 2002, issue of Neuron, suggests that the protein’s protective effects in neurons may explain why adult neurons with axons in the peripheral nervous system survive and regrow after injury, while developing neurons quickly die off. The finding raises the question of whether loss of Hsp27 might have a role in certain neurodegenerative diseases and could perhaps serve as a treatment.