Jump to ContentJump to Main Navigation

Biological Chemistry

Editor-in-Chief: Brüne, Bernhard

Editorial Board Member: Buchner, Johannes / Ludwig, Stephan / Sies, Helmut / Turk, Boris / Wittinghofer, Alfred

12 Issues per year

Access brought to you by:

provisional account

VolumeIssuePage

Issues

Plasminogen-dependent internalization of soluble melanotransferrin involves the low-density lipoprotein receptor-related protein and annexin II

Jonathan Michaud-Levesque1 / Michel Demeule2 / Richard Béliveau3

1Laboratoire de Médecine Moléculaire, Service d'Hémato-Oncologie, Hôpital Ste-Justine, Université du Québec à Montréal, Montréal H3C 3P8, Québec, Canada

2Laboratoire de Médecine Moléculaire, Service d'Hémato-Oncologie, Hôpital Ste-Justine, Université du Québec à Montréal, Montréal H3C 3P8, Québec, Canada

3Laboratoire de Médecine Moléculaire, Service d'Hémato-Oncologie, Hôpital Ste-Justine, Université du Québec à Montréal, Montréal H3C 3P8, Québec, Canada

Corresponding author

Citation Information: Biological Chemistry. Volume 388, Issue 7, Pages 747–754, ISSN (Online) 14316730, ISSN (Print) 14374315, DOI: 10.1515/BC.2007.081, July 2007

Publication History

Received:
2006-11-23
Accepted:
2007-04-03
Published Online:
2007-07-01

Abstract

We investigated the effect of plasminogen (Plg) on the internalization of recombinant soluble melanotransferrin (sMTf) using U87 human glioblastoma cells and murine embryonic fibroblasts (MEF) deficient in the low-density lipoprotein receptor-related protein (LRP). Using biospecific interaction analysis, both Glu- and Lys-Plg were shown to interact with immobilized sMTf. The binding of sMTf at the cell surface increased in the presence of both forms of Plg in control and in LRP-deficient MEF cells, whereas the uptake was strongly stimulated only by Lys-Plg in control MEF and U87 cells. In addition, in the presence of Lys-Plg, the internalization of sMTf was a saturable process, sensitive to temperature and dependent on the integrity of lysine residues. The addition of the receptor-associated protein, lactoferrin and aprotinin, as well as a monoclonal antibody (mAb) directed against LRP, inhibited the Lys-Plg-dependent uptake of sMTf. These results suggest an important role for LRP in this process. In addition, using binding and uptake assays in the presence of anti-annexin II mAb, we showed that annexin II might be responsible for the initial binding of sMTf in the presence of Plg. Our results suggest a Plg-mediated internalization mechanism for the clearance of sMTf via annexin II and LRP.

Keywords: annexin II; endocytosis; low-density lipoprotein receptor-related protein; plasminogen; soluble melanotransferrin

Comments (0)

Please log in or register to comment.