Neurons in the central nervous system that are severed or crushed do not regenerate well. Part of the problem derives from the glial scars left behind after such damage. The scar tissue contains sulfated proteoglycans that seem to inhibit axon regeneration. Shen et al. have now identified a protein tyrosine phosphatase (PTP) in mouse neuronal membranes that functions as a receptor for the proteoglycans. Neurons that lacked this particular PTP showed improved regeneration. Regeneration remained incomplete, presumably due to other inhibitory factors in the way of complete axon regeneration.
Y. Shen, A. P. Tenney, S. A. Busch, K. P. Horn, F. X. Cuascut, K. Liu, Z. He, J. Silver, J. G. Flanagan, PTPσ is a receptor for chondroitin sulfate proteoglycan, an inhibitor of neural regeneration. Science 326, 592–596 (2009). [Abstract] [Full Text]