Formation of the 67‐kDa laminin receptor by acylation of the precursor

Even though the involvement of the 67‐kDa laminin receptor (67LR) in tumor invasiveness has been clearly demonstrated, its molecular structure remains an open problem, since only a full‐length gene encoding a 37‐kDa precursor protein (37LRP) has been isolated so far. A pool of recently obtained monoclonal antibodies directed against the recombinant 37LRP molecule was used to investigate the processing that leads to the formation of the 67‐kDa molecule. In soluble extracts of A431 human carcinoma cells, these reagents recognize the precursor molecule as well as the mature 67LR and a 120‐kDa molecule. The recovery of these proteins was found to be strikingly dependent upon the cell solubilization conditions: the 67LR is soluble in NP‐40‐lysis buffer whereas the 37LRP is NP‐40‐insoluble. Inhibition of 67LR formation by cerulenin indicates that acylation is involved in the processing of the receptor. It is likely a palmitoylation process, as indicated by sensitivity of NP‐40‐soluble extracts to hydroxylamine treatment. Immunoblotting assays performed with a polyclonal serum directed against galectin3 showed that both the 67‐ and the 120‐kDa proteins carry galectin3 epitopes whereas the 37LRP does not. These data suggest that the 67LR is a heterodimer stabilized by strong intramolecular hydrophobic interactions, carried by fatty acids bound to the 37LRP and to a galectin3 cross‐reacting molecule. J. Cell. Biochem. 69:244–251, 1998. © 1998 Wiley‐Liss, Inc.

[1]  S. Ménard,et al.  Production and Characterization of Monoclonal Antibodies Directed against the Laminin Receptor Precursor , 1997, The International journal of biological markers.

[2]  E. Campo,et al.  OVEREXPRESSION OF THE 67‐kD LAMININ RECEPTOR CORRELATES WITH TUMOUR PROGRESSION IN HUMAN COLORECTAL CARCINOMA , 1996, The Journal of pathology.

[3]  G. Pasternack,et al.  Inhibition of fatty acid synthesis delays disease progression in a xenograft model of ovarian cancer. , 1996, Cancer research.

[4]  E. Dratz,et al.  Studies of the structure of the metastasis-associated 67 kDa laminin binding protein: fatty acid acylation and evidence supporting dimerization of the 32 kDa gene product to form the mature protein. , 1995, Biochemistry.

[5]  V. Castronovo,et al.  Galectin-3, a laminin binding protein, fails to modulate adhesion of human melanoma cells to laminin. , 1995, Neoplasma.

[6]  L. Jacobs,et al.  Fatty acid synthesis: a potential selective target for antineoplastic therapy. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[7]  Richard D. Cummings,et al.  Galectins: A family of animal β-galactoside-binding lectins , 1994, Cell.

[8]  S. Ménard,et al.  Prognostic significance of the 67-kilodalton laminin receptor expression in human breast carcinomas. , 1993, Journal of the National Cancer Institute.

[9]  V. Castronovo,et al.  Laminin receptors and laminin-binding proteins during tumor invasion and metastasis. , 1993, Invasion & metastasis.

[10]  E. Campo,et al.  Inverse modulation of steady-state messenger RNA levels of two non-integrin laminin-binding proteins in human colon carcinoma. , 1992, Journal of the National Cancer Institute.

[11]  G. Brawerman,et al.  A 33-kDa polypeptide with homology to the laminin receptor: component of translation machinery. , 1992, Proceedings of the National Academy of Sciences of the United States of America.

[12]  R. Mecham,et al.  Characterization of a putative clone for the 67-kilodalton elastin/laminin receptor suggests that it encodes a cytoplasmic protein rather than a cell surface receptor. , 1991, Biochemistry.

[13]  L. Liotta,et al.  Increased expression of the laminin receptor in human colon cancer. , 1991, Journal of the National Cancer Institute.

[14]  E. Olson,et al.  Identification of a novel fatty acylated protein that partitions between the plasma membrane and cytosol and is deacylated in response to serum and growth factor stimulation. , 1989, The Journal of biological chemistry.

[15]  L. Liotta,et al.  Evidence for a precursor of the high-affinity metastasis-associated murine laminin receptor. , 1989, Biochemistry.

[16]  S. Ōmura,et al.  Binding site of cerulenin in fatty acid synthetase. , 1989, Journal of biochemistry.

[17]  R. Grand,et al.  Acylation of viral and eukaryotic proteins. , 1989, The Biochemical journal.

[18]  J. Wong,et al.  Increased mRNA expression of a laminin-binding protein in human colon carcinoma: complete sequence of a full-length cDNA encoding the protein. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[19]  S. Barondes,et al.  The elastin receptor: a galactoside-binding protein. , 1988, Science.

[20]  J. Gordon,et al.  The biology and enzymology of eukaryotic protein acylation. , 1988, Annual review of biochemistry.

[21]  L. Liotta,et al.  Altered levels of laminin receptor mRNA in various human carcinoma cells that have different abilities to bind laminin. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[22]  H. Strander.  Interferon treatment of human neoplasia. , 1986, Advances in cancer research.

[23]  L. Liotta.  Tumor invasion and metastases--role of the extracellular matrix: Rhoads Memorial Award lecture. , 1986, Cancer research.

[24]  L. Liotta,et al.  Monoclonal antibodies to the human laminin receptor recognize structurally distinct sites. , 1985, Experimental cell research.

[25]  K. Mark,et al.  Isolation of a laminin‐binding protein from muscle cell membranes , 1983, The EMBO journal.

[26]  M. Wicha,et al.  Isolation of a cell surface receptor protein for laminin from murine fibrosarcoma cells , 1983, The Journal of cell biology.

[27]  L. Liotta,et al.  Isolation of a tumor cell laminin receptor. , 1983, Biochemical and biophysical research communications.