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Mol Cell Proteomics. 2013 Dec;12(12):3719-31. doi: 10.1074/mcp.M113.030676. Epub 2013 Sep 10.

The novel caspase-3 substrate Gap43 is involved in AMPA receptor endocytosis and long-term depression.

Author information

1
National Institute of Mental Health, Bethesda, Maryland 20892;

Abstract

The cysteine protease caspase-3, best known as an executioner of cell death in apoptosis, also plays a non-apoptotic role in N-methyl-d-aspartate receptor-dependent long-term depression of synaptic transmission (NMDAR-LTD) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor endocytosis in neurons. The mechanism by which caspase-3 regulates LTD and AMPA receptor endocytosis, however, remains unclear. Here, we addressed this question by using an enzymatic N-terminal peptide enrichment method and mass spectrometry to identify caspase-3 substrates in neurons. Of the many candidates revealed by this proteomic study, we have confirmed BASP1, Dbn1, and Gap43 as true caspase-3 substrates. Moreover, in hippocampal neurons, Gap43 mutants deficient in caspase-3 cleavage inhibit AMPA receptor endocytosis and LTD. We further demonstrated that Gap43, a protein well-known for its functions in axons, is also localized at postsynaptic sites. Our study has identified Gap43 as a key caspase-3 substrate involved in LTD and AMPA receptor endocytosis, uncovered a novel postsynaptic function for Gap43 and provided new insights into how long-term synaptic depression is induced.

PMID:
24023391
PMCID:
PMC3861719
DOI:
10.1074/mcp.M113.030676
[Indexed for MEDLINE]
Free PMC Article

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