Metargidin, a Membrane-anchored Metalloprotease-Disintegrin Protein with an RGD Integrin Binding Sequence

doi:10.1074/jbc.271.9.4593

Metargidin, a Membrane-anchored Metalloprotease-Disintegrin Protein with an RGD Integrin Binding Sequence (*)

From the Cellular Biochemistry and Biophysics Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, New York 10021

** To whom correspondence should be addressed:
Cellular Biochemistry and Biophysics Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, Box 368, 1275 York Ave., New York, NY 10021.
Tel.: 212-639-2915; Fax: 212-717-3047; :c-blobel{at}ski.mskcc.org.

Abstract

Cellular disintegrins are a family of membrane-anchored proteins with structural homology to snake venom metalloproteases and disintegrins. We report here the cDNA cloning and initial biochemical characterization of the first cellular disintegrin protein with an RGD sequence in its disintegrin domain, which we propose to name metargidin (for metalloprotease-RGD-disintegrin protein). The domain organization of metargidin is identical with that of previously reported members of the cellular disintegrin family, comprising (i) a pro- and a metalloprotease domain including a zinc-binding consensus motif, (ii) a disintegrin domain containing the RGD motif, (iii) a cysteine-rich domain, (iv) an epidermal growth factor-like domain, (v) a hydrophobic transmembrane domain, and (vi) a cytoplasmic tail with proline-rich sequences that could act as potential SH3 ligands. Antibodies raised against the cytoplasmic tail of metargidin recognize a glycoprotein of 110 kDa in MDA-MB-468 mammary epithelial carcinoma cells, which can be cell surface-biotinylated, indicating its localization in the plasma membrane. A second protein of 56 kDa co-immunoprecipitates with metargidin, suggesting that it is part of a protein complex. These features are consistent with a model in which metargidin is an integrin ligand which, as a transmembrane protein, might function in cell-cell adhesion and/or signaling.

Footnotes

↵^§ Supported by Schering AG Berlin. Present address: Institute of Cellular and Molecular Biology, Research Laboratories of Schering AG, D-13342 Berlin, Germany.
↵^¶ Supported by National Institutes of Health Training Grant 5T32GM07739-17 and enrolled in the Tri-Institutional (Cornell/ Rockefeller University/Memorial Sloan-Kettering Cancer Center) MD/Ph.D. training program.
↵* This work was supported in part by Cancer Center Support Grant NCI-P31-CA-08748. 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.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank(™)/EMBL Data Bank with accession number(s) U41767[GenBank].
↵¹ The abbreviations used are:

PCR

polymerase chain reaction

GST

glutathione S-transferase

DTT

dithiothreitol.
- Received November 27, 1995.
- Revision received January 2, 1996.