Alpha-1 antitrypsin binds preprohepcidin intracellularly and prohepcidin in the serum.
FEBS J
; 276(7): 2012-21, 2009 Apr.
Article
en En
| MEDLINE
| ID: mdl-19292870
ABSTRACT
Recent discoveries have indicated that the hormone hepcidin plays a major role in the control of iron homeostasis. Hepcidin regulates the iron level in the blood through the interaction with ferroportin, an iron exporter molecule, causing its internalization and degradation. As a result, hepcidin increases cellular iron sequestration, and decreases the iron concentration in the plasma. Only mature hepcidin (result of the cleavage of prohepcidin by furin proteases) has biological activity; however, prohepcidin, the prohormone form, is also present in the plasma. In this study, we aimed to identify new protein-protein interactions of preprohepcidin, prohepcidin and hepcidin using the BacterioMatch two-hybrid system. Screening assays were carried out on a human liver cDNA library. Preprohepcidin screening gave the following results:
alpha-1 antitrypsin, transthyretin and alpha-1-acid glycoprotein showed strong interactions with preprohepcidin. We further confirmed and examined the alpha-1 antitrypsin binding in vitro (glutathione S-transferase, pull down, coimmunoprecipitation, MALDI-TOF) and in vivo (ELISA, cross-linking assay). Our results demonstrated that the serine protease inhibitor alpha-1 antitrypsin binds preprohepcidin within the cell during maturation. Furthermore, alpha-1 antitrypsin binds prohepcidin significantly in the plasma. This observation may explain the presence of prohormone in the circulation, as well as the post-translational regulation of the mature hormone level in the blood. In addition, the lack of cleavage protection in patients with alpha-1 antitrypsin deficiency may be the reason for the disturbance in their iron homeostasis.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Precursores de Proteínas
/
Alfa 1-Antitripsina
/
Péptidos Catiónicos Antimicrobianos
Límite:
Humans
Idioma:
En
Revista:
FEBS J
Asunto de la revista:
BIOQUIMICA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Hungria