These authors contributed equally to this work.
Calpain-truncated CRMP-3 and -4 contribute to potassium deprivation-induced apoptosis of cerebellar granule neurons
Article first published online: 28 JUL 2009
Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Volume 9, Issue 14, pages 3712–3728, No. 14 July 2009
How to Cite
Liu, W., Zhou, X.-w., Liu, S., Hu, K., Wang, C., He, Q. and Li, M. (2009), Calpain-truncated CRMP-3 and -4 contribute to potassium deprivation-induced apoptosis of cerebellar granule neurons. Proteomics, 9: 3712–3728. doi: 10.1002/pmic.200800979
- Issue published online: 28 JUL 2009
- Article first published online: 28 JUL 2009
- Manuscript Accepted: 13 APR 2009
- Manuscript Revised: 27 MAR 2009
- Manuscript Received: 24 DEC 2008
- NSFC. Grant Numbers: U0632006, 30629002, 30870786 to M-T Li, 30870988 to X-W Zhou
- Calpain substrates;
Increasing evidence shows that calpain-mediated proteolytic processing of a selective number of proteins plays an important role in neuronal apoptosis. Study of calpain-mediated cleavage events and related functions may contribute to a better understanding of neuronal apoptosis and neurodegenerative diseases. We, therefore, investigated the role of calpain substrates in potassium deprivation-induced apoptosis of cerebellar granule neurons (CGNs). Twelve previously known and seven novel candidates of calpain substrates were identified by 2-D DIGE and MALDI-TOF/TOF MS analysis. Further, the identified novel calpain substrates were validated by Western blot analysis. Moreover, we focused on the collapsin response mediator proteins (CRMP-1, -2, -3 and -4 isoforms) and found that CRMPs were proteolytically processed by calpain but not by caspase, both in vivo and in vitro. To clarify the properties of the calpain-mediated proteolysis of CRMPs, we constructed the deletion mutants of CRMPs for additional biochemical studies. In vitro cleavage assays revealed that CRMP-1, -2 and -4 were truncated by calpain at the C-terminus, whereas CRMP-3 was cleaved at the N-terminus. Finally, we assessed the role of CRMPs in the process of potassium deprivation-triggered neuronal apoptosis by overexpressing the truncated CRMPs in CGNs. Our data clearly showed that the truncated CRMP-3 and -4, but not CRMP-1 and -2, significantly induced neuronal apoptosis. These findings demonstrated that calpain-truncated CRMP-3 and -4 act as pro-apoptotic players when CGNs undergo apoptosis.