E.T. and S.K. contributed equally to this work.
Calpain-mediated cleavage of collapsin response mediator protein(CRMP)-2 during neurite degeneration in mice
Article first published online: 4 DEC 2007
European Journal of Neuroscience
Volume 26, Issue 12, pages 3368–3381, December 2007
How to Cite
Touma, E., Kato, S., Fukui, K. and Koike, T. (2007), Calpain-mediated cleavage of collapsin response mediator protein(CRMP)-2 during neurite degeneration in mice. European Journal of Neuroscience, 26: 3368–3381. doi: 10.1111/j.1460-9568.2007.05943.x
- Issue published online: 4 DEC 2007
- Article first published online: 4 DEC 2007
- Received 23 May 2007, revised 7 October 2007, accepted 16 October 2007
- sympathetic ganglia
Axon or dendrite degeneration involves activation of the ubiquitin–proteasome system, failure to maintain neuritic ATP levels, microtubule fragmentation and a mitochondrial permeability transition that occur independently of the somal death programs. To gain further insight into the neurite degeneration mechanims we have compared two-dimensional gel electrophoresis patterns of neurite proteins from suprior cervical ganglia during degeneration caused by nerve growth factor (NGF) deprivation. We show here that collapsin response mediator protein (CRMP)-2 and CMRP-4 protein patterns were altered during beading formation, an early hallmark of neurite degeneration, prior to neurite fragmentation, the final stage of degeneration. Western blotting using a monoclonal antibody against CRMP-2 shows that the native form (64 kDa) was cleaved to generate a truncated form (58 kDa). No cleavage of CRMP-2 or -4 occurred in NGF-deprived neurites from Wld s (Wallerian degeneration slow) mutant mice in which neurite degeneration is markedly delayed. Using different protease inhibitors, purified calpain 1 protein and calpain 1-specific siRNA, we have demonstrated that CRMP-2 is a substrate for calpain 1. Indeed, caplain activity was activated at an early phase of neuronal degeneration in cerebellar granule neurons, and down-regulation of caplain 1 expression suppressed CRMP-2 cleavage. Furthermore, this cleavage occurred after vinblastine treatment or in vitro Wallerian degeneration, suggesting that it represents a common step in the process of dying neurites. CRMP-2 and -4 play a pivotal role in axonal growth and transport, and the C-terminus region of CRMP-2 is essential for its binding to kinesin-1. Hence, this cleavage will render them dysfunctional and subject to autophagic processing associated with beading formation, as evidenced by the finding that the truncated form was localized in the beadings.