Dataset Information

Time-resolved N-terminome analysis of HCT116 cells during apoptosis

ABSTRACT: Proteins' N-termini contain information about their biochemical properties and functions, and they can undergo co- or post-translational modifications, as well as be processed by proteases. To expand the coverage of the N-terminome, we have developed LATE (LysN Amino Terminal Enrichment), a method that uses selective chemical derivatization of α-amines to isolate the N-terminal peptides. We applied LATE in combination with other N-terminomic method to study caspase-3 mediated proteolysis both in vitro and during apoptosis in cells. This enable us to identify many unreported caspase-3 cleavages, including some that cannot be identified by other methods. Furthermore, we find direct evidence that some of the caspase-3 generated neo-N-termini can be further modified by Nt-acetylation. This provides a global picture of the caspase-3 degradome and uncovers previously unrecognised functional crosstalk between post-translational Nt-acetylation and caspase proteolysis pathways.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Oded Kleifeld

LAB HEAD: Oded Kleifeld

PROVIDER: PXD040732 | Pride | 2023-06-27

REPOSITORIES: Pride

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Publications

In-Depth Characterization of Apoptosis N-Terminome Reveals a Link Between Caspase-3 Cleavage and Posttranslational N-Terminal Acetylation.

Hanna Rawad R Rozenberg Andrey A Saied Layla L Ben-Yosef Daniel D Lavy Tali T Kleifeld Oded O

Molecular & cellular proteomics : MCP 20230524 7

The N termini of proteins contain information about their biochemical properties and functions. These N termini can be processed by proteases and can undergo other co- or posttranslational modifications. We have developed LATE (LysN Amino Terminal Enrichment), a method that uses selective chemical derivatization of α-amines to isolate the N-terminal peptides, in order to improve N-terminome identification in conjunction with other enrichment strategies. We applied LATE alongside another N-termin ...[more]

PMID: 37236440

Similar Datasets

Project description:Co-translational N-terminal (Nt-) acetylation of nascent polypeptides is catalyzed by N-terminal acetyltransferases (NATs). The very N-terminal amino acid sequence is the major factor determining whether or not a given protein is Nt-acetylated. In humans, six different NATs, denoted NatA-NatF, are identified. In the current study we used N-terminal COFRADIC analysis to define the in vivo substrate specificity of Naa50 (Nat5)/NatE as this has long remained elusive. Three yeast strains were generated; a control strain endogenously expressing yNaa50, a deletion strain depleted of yNaa50 and a strain deleted of yNaa50 but ectopically expressing human Naa50. When comparing the Nt-acetylation status of different N-termini in the control strain with the deletion strain, a reduction in Nt-acetylation for several yeast proteins was observed. To our surprise, these substrates were not of the predicted NatE-type substrates, but rather canonical NatA substrates. Further, ectopic expression of hNaa50 mainly resulted in the Nt-acetylation of a selected class of otherwise Nt-free yeast N-termini besides increasing the degree of Nt-acetylation of several other yeast proteins, and as such (partially) complementing those N-termini displaying reduced Nt-acetylation upon yNAA50-deletion. The preferred substrates of hNaa50 were predominantly Met-starting N-termini including Met-Lys-, Met-Val-, Met-Ala-, Met-Tyr-, Met-Phe-, Met-Leu-, Met-Ser- and Met-Thr, and highly overlapped with the previously identified human Naa60/NatF substrate specificity profile. Identification of several hNaa50 substrates with a small amino acid in the second position also revealed a potential interplay between the NATs and methionine aminopeptidases (MetAPs). The initiator Methionine (iMet) is normally cleaved off by MetAPs when the second amino acid is small, but our in vitro data suggest that in contrast to a free iMet, an Nt-acetylated iMet is not hydrolyzed by MetAPs. Thus, Naa50-mediated Nt-acetylation may potentially act as a mechanism to retain the iMet of proteins with a small amino acid at the second position that normally would be hydrolyzed.

			Action	DRS
	Files_list.txt	Txt
	HUMAN_CRAP_DECOY.fasta	Fasta
	Seq77781_88min_HF.mzML	Mzml
	Seq77781_88min_HF.raw	Raw
	Seq77782_88min_HF.mzML	Mzml