Adelaide Research and Scholarship
Schools and Disciplines
School of Molecular and Biomedical Science
Microbiology and Immunology
Microbiology and Immunology publications
Please use this identifier to cite or link to this item:
|Type: ||Journal article|
|Title: ||The Escherichia coli subtilase cytotoxin A subunit specifically cleaves cell-surface GRP78 protein and abolishes COOH-terminal-dependent signaling|
|Author: ||Ray, R.|
de Ridder, G.
|Citation: ||Journal of Biological Chemistry, 2012; 287(39):32755-32769|
|Publisher: ||Amer Soc Biochemistry Molecular Biology Inc|
|Issue Date: ||2012|
|Rupa Ray, Gustaaf G. de Ridder, Jerry P. Eu, Adrienne W. Paton, James C. Paton and Salvatore V. Pizzo|
|Abstract: ||GRP78, a molecular chaperone with critical endoplasmic reticulum functions, is aberrantly expressed on the surface of cancer cells, including prostate and melanoma. Here it functions as a pro-proliferative and anti-apoptotic signaling receptor via NH2-terminal domain ligation. Auto-antibodies to this domain may appear in cancer patient serum where they are a poor prognostic indicator. Conversely, GRP78 COOH-terminal domain ligation is pro-apoptotic and anti-proliferative. There is no method to disrupt cell-surface GRP78 without compromising the total GRP78 pool, making it difficult to study cell-surface GRP78 function. We studied six cell lines representing three cancer types. One cell line per group expresses high levels of cell-surface GRP78, and the other expresses low levels (human hepatoma: Hep3B and HepG2; human prostate cancer: PC3 and 1-LN; murine melanoma: B16F0 and B16F1). We investigated the effect of Escherichia coli subtilase cytoxin catalytic subunit (SubA) on GRP78. We report that SubA specifically cleaves cell-surface GRP78 on HepG2, 1-LN, and B16F1 cells without affecting intracellular GRP78. B16F0 cells (GRP78low) have lower amounts of cleaved cell-surface GRP78. SubA has no effect on Hep3B and PC3 cells. The predicted 28-kDa GRP78 COOH-terminal fragment is released into the culture medium by SubA treatment, and COOH-terminal domain signal transduction is abrogated, whereas pro-proliferative signaling mediated through NH2-terminal domain ligation is unaffected. These experiments clarify cell-surface GRP78 topology and demonstrate that the COOH-terminal domain is necessary for pro-apoptotic signal transduction occurring upon COOH-terminal antibody ligation. SubA is a powerful tool to specifically probe the functions of cell-surface GRP78.|
|Keywords: ||Animals; Humans; Mice; Escherichia coli; Melanoma; Prostatic Neoplasms; Subtilisins; Escherichia coli Proteins; Heat-Shock Proteins; Receptors, G-Protein-Coupled; Antibodies, Neoplasm; Autoantibodies; Signal Transduction; Catalytic Domain; Male; Hep G2 Cells; Proteolysis|
|Rights: ||© 2012 by The American Society for Biochemistry and Molecular Biology, Inc.|
|Appears in Collections:||Microbiology and Immunology publications|
|View citing articles in: ||Web of Science|
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.