HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Data Supplement Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lacroix, M. Articles by Thielens, N. M. Search for Related Content PubMed PubMed Citation Articles by Lacroix, M. Articles by Thielens, N. M.

Residue Lys⁵⁷ in the Collagen-Like Region of Human L-Ficolin and Its Counterpart Lys⁴⁷ in H-Ficolin Play a Key Role in the Interaction with the Mannan-Binding Lectin-Associated Serine Proteases and the Collectin Receptor Calreticulin¹

Monique Lacroix^*, Chantal Dumestre-Pérard, Guy Schoehn^*,, Gunnar Houen, Jean-Yves Cesbron, Gérard J. Arlaud^* and Nicole M. Thielens^2,*

^* Institut de Biologie Structurale Jean-Pierre Ebel, Unité Mixte de Recherche (UMR) 5075, Centre National de la Recherche Scientifique (CNRS)-Commissariat à l’Energie Atomique, Université Joseph Fourier, Grenoble, France; Laboratoire Adaptation et Pathogénie des Microorganismes, Université Joseph Fourier, UMR 5163, CNRS, Grenoble, France; Unit for Virus Host Cell Interaction, UMR 5233, European Molecular Biology Laboratory-CNRS, Université Joseph Fourier, Grenoble, France; and Department of Autoimmunology, Statens Serum Institut, Copenhagen, Denmark

L- and H-ficolins are serum oligomeric defense proteins consisting of a collagen-like region and a fibrinogen-like recognition domain that bind to pathogen- and apoptotic cell-associated molecular patterns. They share with mannan-binding lectin (MBL) the ability to associate with MBL-associated serine proteases (MASP)-1, -2, -3, and protein MAp19 and to trigger the lectin complement pathway through MASP-2 activation. Recent studies have revealed the essential role of Lys⁵⁵ in the collagenous region of MBL in the interaction with the MASPs and calreticulin (CRT). To test the possible involvement of the homologous residues Lys⁵⁷ of L-ficolin and Lys⁴⁷ of H-ficolin, point mutants of both proteins were produced in which these residues were mutated to Ala, Glu, or Arg. The resulting mutants exhibited oligomerization patterns and ligand binding properties similar to those of their wild-type counterparts. In contrast, all three mutations strongly inhibited the interaction of L- and H-ficolins with MAp19 and MASP-2 and impaired the ability of each ficolin to trigger the lectin pathway. In the case of MASP-1 and MASP-3, replacement of the target Lys residues by Ala or Glu abolished interaction, whereas the Lys to Arg mutations had only slight inhibitory effects. Likewise, binding of each ficolin to CRT was inhibited by mutation of Lys to Ala or Glu, but not to Arg. In conclusion, residues Lys⁵⁷ of L-ficolin and Lys⁴⁷ of H-ficolin are key components of the interaction with the MASPs and CRT, providing strong indication that MBL and the ficolins share homologous binding sites for both types of proteins.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ This work was supported by the Commissariat à l’Energie Atomique, the Centre National de la Recherche Scientifique, the Université Joseph Fourier (Grenoble, France).

² Address correspondence and reprint requests to Dr. Nicole Thielens, Laboratoire d’Enzymologie Moléculaire, Institut de Biologie Structurale Jean-Pierre Ebel, 41 Rue Jules Horowitz, 38027 Grenoble Cedex 1, France. E-mail address: nicole.thielens{at}ibs.fr

³ Abbreviations used in this paper: FBG, fibrinogen-like; cC1qR, receptor for collagenous domain of C1q; CRT, calreticulin; EGF, epidermal growth factor; GlcNAc, N-acetyl-D-glucosamine; MASP, MBL-associated serine protease; MBL, mannan-binding lectin; SPR, surface plasmon resonance.

⁴ The online version of this article contains supplemental material.

This article has been cited by other articles:

				I. Bally, V. Rossi, T. Lunardi, N. M. Thielens, C. Gaboriaud, and G. J. Arlaud Identification of the C1q-binding Sites of Human C1r and C1s: A REFINED THREE-DIMENSIONAL MODEL OF THE C1 COMPLEX OF COMPLEMENT J. Biol. Chem., July 17, 2009; 284(29): 19340 - 19348. [Abstract] [Full Text] [PDF]

				L. Munthe-Fog, T. Hummelshoj, C. Honore, H. O. Madsen, H. Permin, and P. Garred Immunodeficiency Associated with FCN3 Mutation and Ficolin-3 Deficiency N. Engl. J. Med., June 18, 2009; 360(25): 2637 - 2644. [Abstract] [Full Text] [PDF]