TY - JOUR
T1 - Mass spectrometry characterization of light chain fragmentation sites in cardiac AL amyloidosis
T2 - Insights into the timing of proteolysis
AU - Lavatelli, Francesca
AU - Mazzini, Giulia
AU - Ricagno, Stefano
AU - Iavarone, Federica
AU - Rognoni, Paola
AU - Milani, Paolo
AU - Nuvolone, Mario
AU - Swuec, Paolo
AU - Caminito, Serena
AU - Tasaki, Masayoshi
AU - Chaves, Antonio Sanjuan
AU - Urbani, Andrea
AU - Merlini, Giampaolo
AU - Palladini, Giovanni
N1 - Funding Information:
Funding and additional information—This work was supported by Fondazione Cariplo Grants 2015-0591 (to G. P.) and 2016-0489 (to F. L.), Associazione Italiana per la Ricerca sul Cancro special program “5 per mille” Grant 9965 (to G. Merlini), the Italian Ministry of Health Grants RF-2013-02355259 (to G. Merlini) and RF-2016-02361756 (to G. P.), the Italian Medicines Agency Grant AIFA-2016-02364602 (to G. P.), and the European Joint Programme on Rare Diseases E-RARE JTC 2016 Grant ReDox (to G. P.).
Publisher Copyright:
© 2020 American Society for Biochemistry and Molecular Biology Inc.. All rights reserved.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/12/4
Y1 - 2020/12/4
N2 - Amyloid fibrils are polymeric structures originating from aggregation of misfolded proteins. In vivo, proteolysis may modulate amyloidogenesis and fibril stability. In light chain (AL) amyloidosis, fragmented light chains (LCs) are abundant components of amyloid deposits; however, site and timing of proteolysis are debated. Identification of the N and C termini of LC fragments is instrumental to understanding involved processes and enzymes. We investigated theN and C terminome of the LC proteoforms in fibrils extracted from the hearts of two AL cardiomyopathy patients, using a proteomic approach based on derivatization of N- and C-terminal residues, followed by mapping of fragmentation sites on the structures of native and fibrillar relevant LCs. We provide the first high-specificity map of proteolytic cleavages in natural AL amyloid. Proteolysis occurs both on the LC variable and constant domains, generating a complex fragmentation pattern. The structural analysis indicates extensive remodeling by multiple proteases, largely taking place on poorly folded regions of the fibril surfaces. This study adds novel important knowledge on amyloid LC processing: although our data do not exclude that proteolysis of native LC dimers may destabilize their structure and favor fibril formation, the data show that LC deposition largely precedes the proteolytic events documentable in mature AL fibrils.
AB - Amyloid fibrils are polymeric structures originating from aggregation of misfolded proteins. In vivo, proteolysis may modulate amyloidogenesis and fibril stability. In light chain (AL) amyloidosis, fragmented light chains (LCs) are abundant components of amyloid deposits; however, site and timing of proteolysis are debated. Identification of the N and C termini of LC fragments is instrumental to understanding involved processes and enzymes. We investigated theN and C terminome of the LC proteoforms in fibrils extracted from the hearts of two AL cardiomyopathy patients, using a proteomic approach based on derivatization of N- and C-terminal residues, followed by mapping of fragmentation sites on the structures of native and fibrillar relevant LCs. We provide the first high-specificity map of proteolytic cleavages in natural AL amyloid. Proteolysis occurs both on the LC variable and constant domains, generating a complex fragmentation pattern. The structural analysis indicates extensive remodeling by multiple proteases, largely taking place on poorly folded regions of the fibril surfaces. This study adds novel important knowledge on amyloid LC processing: although our data do not exclude that proteolysis of native LC dimers may destabilize their structure and favor fibril formation, the data show that LC deposition largely precedes the proteolytic events documentable in mature AL fibrils.
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U2 - 10.1074/jbc.RA120.013461
DO - 10.1074/jbc.RA120.013461
M3 - Article
C2 - 32952127
AN - SCOPUS:85097571134
VL - 295
SP - 16572
EP - 16584
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 49
ER -