A novel ligand in lymphocyte-mediated cytotoxicity: expression of the beta subunit of H+ transporting ATP synthase on the surface of tumor cell lines.
Open Access
- 1 July 1994
- journal article
- Published by Rockefeller University Press in The Journal of Experimental Medicine
- Vol. 180 (1) , 273-281
- https://doi.org/10.1084/jem.180.1.273
Abstract
Extracellular adenosine triphosphate (eATP) has been suggested to play a role in lymphocyte-induced tumor destruction. We now provide evidence that a protein responsible for ATP synthesis in mitochondria may also play a physiologic role in major histocompatibility complex-independent, lymphocyte-mediated cytotoxicity. A 51.5-kD protein (p51.5) bearing structural and immunologic characteristics of the beta subunit of H+ transporting ATP synthase (E.C. 3.6.1.34, beta-H+ATPase, published molecular mass of 51.6 kD) was detected on the plasma membrane of three different human tumor cell lines studied. NH2-terminal amino acid sequence analysis of purified p51.5 from K562 tumor cells revealed 100% homology of 16 residues identified in the first 21 positions to the known sequence of human mitochondrial beta-H+ ATPase. Antibody directed against a 21-mer peptide in the ATP binding region of beta-H+ ATPase (anti-beta) reacted with only one band on Western blots of whole tumor extracts and tumor membrane extracts suggesting that the antiserum reacts with a single species of protein. Anti-beta reacted with the cell membranes of tumor cells as determined by fluorescence-activated flow cytometry and immunoprecipitated a 51.5-kD protein from surface-labeled neoplastic cells (but not human erythrocytes and lymphocytes). Purified p51.5 bound to human lymphocytes and inhibited natural killer (NK) cell-mediated cytotoxicity. Furthermore, anti-beta treatment of the K562 and A549 tumor cell lines inhibited NK (by > 95%) and interleukin 2-activated killer (LAK) cell (by 75%) cytotoxicity, respectively. Soluble p51.5 upon binding to lymphocytes retained its reactivity to anti-beta suggesting that the ATP binding domain and the lymphocyte-receptor binding domain reside in distinct regions of the ligand. These results suggest that beta-H+ ATPase or a nearly identical molecule is an important ligand in the effector phase (rather than the recognition phase) of a cytolytic pathway used by naive NK and LAK cells.Keywords
This publication has 43 references indexed in Scilit:
- Extracellular ATP as a possible mediator of cell-mediated cytotoxicityImmunology Today, 1990
- The H+-ATP Synthase of Mitochondria in Tissue Regeneration and NeoplasiaAnnals of the New York Academy of Sciences, 1988
- Multiple mechanisms of lymphocyte-mediated killingImmunology Today, 1988
- Mechanism of Cytotoxicity by Natural Killer (NK) CellsAnnual Review of Immunology, 1986
- Changes in activity and F1 content of mitochondrial H+‐ATPase in regenerating rat liverFEBS Letters, 1985
- Expression of protease and protease-inhibitory activity in human mononuclear leukocyte cultures: Effect of conA stimulationExperimental Cell Research, 1982
- Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.Proceedings of the National Academy of Sciences, 1979
- A Rapid and Sensitive Method for the Quantitation of Microgram Quantities of Protein Utilizing the Principle of Protein-Dye BindingAnalytical Biochemistry, 1976
- Observations on the mechanism by which T-lymphocytes exert cytotoxic effectsNature, 1974
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970