Proteoform-Resolved Profiling of Plasminogen Activation Reveals Novel Abundant Phosphorylation Site and Primary N-Terminal Cleavage Site.
Mol Cell Proteomics
; 23(1): 100696, 2024 Jan.
Article
en En
| MEDLINE
| ID: mdl-38101751
ABSTRACT
Plasminogen (Plg), the zymogen of plasmin (Plm), is a glycoprotein involved in fibrinolysis and a wide variety of other physiological processes. Plg dysregulation has been implicated in a range of diseases. Classically, human Plg is categorized into two types, supposedly having different functional features, based on the presence (type I) or absence (type II) of a single N-linked glycan. Using high-resolution native mass spectrometry, we uncovered that the proteoform profiles of human Plg (and Plm) are substantially more extensive than this simple binary classification. In samples derived from human plasma, we identified up to 14 distinct proteoforms of Plg, including a novel highly stoichiometric phosphorylation site at Ser339. To elucidate the potential functional effects of these post-translational modifications, we performed proteoform-resolved kinetic analyses of the Plg-to-Plm conversion using several canonical activators. This conversion is thought to involve at least two independent cleavage events one to remove the N-terminal peptide and another to release the active catalytic site. Our analyses reveal that these processes are not independent but are instead tightly regulated and occur in a step-wise manner. Notably, N-terminal cleavage at the canonical site (Lys77) does not occur directly from intact Plg. Instead, an activation intermediate corresponding to cleavage at Arg68 is initially produced, which only then is further processed to the canonical Lys77 product. Based on our results, we propose a refined categorization for human Plg proteoforms. In addition, we reveal that the proteoform profile of human Plg is more extensive than that of rat Plg, which lacks, for instance, the here-described phosphorylation at Ser339.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Plasminógeno
/
Fibrinolisina
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Mol Cell Proteomics
Asunto de la revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Países Bajos