MMP-9 sheds the beta2 integrin subunit (CD18) from macrophages.
Mol Cell Proteomics
; 8(5): 1044-60, 2009 May.
Article
em En
| MEDLINE
| ID: mdl-19116209
ABSTRACT
Activated macrophages are essential effectors of immunity and a rich source of matrix metalloproteinase-9 (MMP-9; gelatinase B). To search for cellular substrates of the enzyme, we subjected wild-type macrophages and macrophages expressing an autoactivating form of pro-MMP-9 (M9A macrophages) to proteomics analysis. Two-dimensional liquid chromatography together with tandem mass spectrometry identified 467 proteins in medium conditioned by M9A and/or wild-type macrophages. Subtractive proteomics identified 18 candidate MMP-9 substrates. Biochemical studies confirmed that two transmembrane proteins, beta(2) integrin subunit (CD18) and amyloid protein precursor (APP), were enriched in the medium of M9A macrophages. To identify potential cleavage sites, we synthesized an overlapping library of peptides that spanned 60 residues of the ectodomain and transmembrane domain of beta(2) integrin. Active MMP-9 cleaved a single peptide, ECVKGPNVAAIVGGT, at residues corresponding to Ala(705) and Ile(706) of the beta(2) integrin. Peptides corresponding to this cleavage site were detected by tandem mass spectrometric analysis only in medium from M9A macrophages, strongly supporting the proposal that beta(2) integrin is shed by autoactivating MMP-9. Our observations indicate that subtractive proteomics in concert with peptide substrate mapping is a powerful approach for identifying proteolytic substrates and suggest that MMP-9 plays previously unsuspected roles in the regulation and shedding of beta(2) integrin.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Antígenos CD18
/
Metaloproteinase 9 da Matriz
/
Subunidades Proteicas
/
Macrófagos
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Mol Cell Proteomics
Assunto da revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Estados Unidos