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Metacaspase9 substrates - 35S:MC9 / mc9

N-terminus Proteolysis in Arabidopsis thaliana

178 modifications in 178 peptides, found in 308 proteins

Experiment Details

Exp 51b


Experimental Setup
TissueSeedlings 2d
Condition35S:MC9 / mc9
PTM EnrichmentN-terminal COFRADIC
MS InstrumentLTQ Orbitrap XL
MS/MS Search Parameters
Protein DatabaseTAIR10 (27,416 entries)
Decoy Strategysee Supplemental Methods 3 (Käll et al, 2008)
FDR ThresholdFDR 0.52%
Search Algorithm(s)MASCOT
Precursor Mass Tolerance10 ppm
Identification ScoreMASCOT Score
Protease semi-ArgC/P
Fixed ModificationsCarbamidomethyl (C)
Variable ModificationsOxidation (M)
Pyro-glu from Q
LabelsButyrylation light/heavy (+70.042/+74.056 Da) (Peptide N-term)
Butyrylation light/heavy (+70.042/+74.056 Da) (K)
Other Information
CommentsSupplemental Dataset S1B. Log2 fold changes are displayed for the peptide intensity ratio of 35S:MC9 / mc9.


Publication Information

Tsiatsiani et al., 2013

PubMed ID: 23964026

ProteomeXchange: PRD000664

Abstract

Plant Cell. 2013 Aug;25(8):2831-47. doi: 10.1105/tpc.113.115287. Epub 2013 Aug 
20.

The Arabidopsis metacaspase9 degradome.

Tsiatsiani L(1), Timmerman E, De Bock PJ, Vercammen D, Stael S, van de Cotte B, 
Staes A, Goethals M, Beunens T, Van Damme P, Gevaert K, Van Breusegem F.

Author information:
(1)Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium.

Metacaspases are distant relatives of the metazoan caspases, found in plants, 
fungi, and protists. However, in contrast with caspases, information about the 
physiological substrates of metacaspases is still scarce. By means of N-terminal 
combined fractional diagonal chromatography, the physiological substrates of 
metacaspase9 (MC9; AT5G04200) were identified in young seedlings of Arabidopsis 
thaliana on the proteome-wide level, providing additional insight into MC9 
cleavage specificity and revealing a previously unknown preference for acidic 
residues at the substrate prime site position P1'. The functionalities of the 
identified MC9 substrates hinted at metacaspase functions other than those 
related to cell death. These results allowed us to resolve the substrate 
specificity of MC9 in more detail and indicated that the activity of 
phosphoenolpyruvate carboxykinase 1 (AT4G37870), a key enzyme in 
gluconeogenesis, is enhanced upon MC9-dependent proteolysis.

DOI: 10.1105/tpc.113.115287
PMCID: PMC3784583
PMID: 23964026 [Indexed for MEDLINE]