Identification of the Binding Domain for Secretory Phospholipases A
on Their M-type 180-kDa Membrane Receptor *
- From the Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
- ¶ To whom all correspondence should be addressed. Tel.: 33-93-95-77-00 or −02; Fax: 33-93-95-77-04. douy{at}unice.fr.
Abstract
The rabbit muscle (M)-type receptor for secretory phospholipases A
(sPLA
s) has a large extracellular domain of 1394 amino acids, composed of an N-terminal cysteine-rich domain, a fibronectin-like
type II domain, and eight carbohydrate recognition domains (CRDs). It is thought to mediate some of the physiological effects
of mammalian sPLA
s, including vascular smooth muscle contraction and cell proliferation, and is able to internalize sPLA
s. Here, we show by site-directed mutagenesis that OS
, a snake venom sPLA
, binds to the receptor via its CRDs and that deletion of CRD 5 completely abolishes the binding of sPLA
s. Moreover, a receptor lacking all CRDs but CRD 5 was still able to bind OS
although with a lower affinity. Deletion of CRDs 4 and 6, surrounding the CRD 5, slightly reduced the affinity for OS
, thus suggesting that these CRDs are also involved in the binding of OS
. The M-type sPLA
receptor and the macrophage mannose receptor are homologous and are predicted to share the same tertiary structure. p-Aminophenyl-α-D-mannopyranoside bovine serum albumin, a known ligand of the macrophage mannose receptor, binds to the M-type
sPLA
receptor essentially via CRDs 3-6.
Footnotes
-
↵§ Recipient of Grant DRET from the Délégation Générale pour l'Armement, Ministère de la Défense Nationale.
-
↵* This work was supported by CNRS, the Association pour la Recherche sur le Cancer (ARC), and the Ministère de la Défense Nationale (Grant DRET 93/122). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- sPLA
-
secretory phospholipase A
- CRD
-
carbohydrate recognition domain
- mannose-BSA
-
p-aminophenyl-α-D-mannopyranoside bovine serum albumin
- M-type
-
muscle-type
- PBS
-
phosphate-buffered saline.
- sPLA
-
↵2J.-P. Nicolas, G. Lambeau, and M. Lazdunski, unpublished observations.
-
- Received June 16, 1995.
- Revision received August 31, 1995.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
