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Role of a Guanine Nucleotide‐Binding Regulatory Protein in the Hydrolysis of Phosphatidylinositol 4,5‐Bisphosphate in a Human T Cell Line
Author(s) -
HasegawaSasaki Hiroko,
Lutz Frieder,
Sasaki Terukatsu
Publication year - 1988
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.1988.tb01389.x
Subject(s) - jurkat cells , phosphatidylinositol 4,5 bisphosphate , phosphatidylinositol , inositol , biology , guanine nucleotide exchange factor , gtp' , biochemistry , guanine , g protein , guanosine , microbiology and biotechnology , gq alpha subunit , nucleotide , inositol trisphosphate , signal transduction , t cell , receptor , enzyme , immune system , gene , immunology
The CD3(T3)/antigen receptor complex appears to function by transducing an antigen signal presented by macrophages into the hydrolysis of phosphatidylinositol 4,5‐bisphosphate [PtdIns(4,5) P 2 ]. In order to find out how the CD3/antigen receptor complex regulates the hydrolysis of PtdIns(4,5) P 2 to diacylglycerol and inositol trisphosphate, we investigated the possible role played by a guanine nucleotide‐binding regulatory protein in PtdIns(4,5) P 2 hydrolysis in a human T cell leukemia line, JURKAT. JURKAT cells were made permeable to Al 3+ , F − , GTP, and a nonhydrolyzable GTP analogue, guanosine 5′‐ O ‐(3‐thiotriphosphate) (GTP γ S), by treatment with pseudomonal cytotoxin. In the presence of AlCl 3 NaF stimulated the release of inositol phosphates in the cytotoxin‐treated JURKAT cells. NaF plus AlCl 3 induced increases in inositol tris‐, bis‐, and mono‐phosphates and decreases in PtdIns(4,5) P 2 , phosphatidylinositol 4‐phosphate, and phosphatidylinositol within 5 min after addition to the cytotoxin‐treated cells at 37 C. GTP γ S stimulated, to some extent, polyphosphoinositide hydrolysis in the cytotoxin‐treated JURKAT. The cytotoxin‐treated JURKAT cells retained the ability to respond to anti‐Leu‐4 with polyphosphoinositide hydrolysis. It has been shown that Al 3+ in the presence of F − modulates the activity of various guanine nucleotide‐binding regulatory proteins. Therefore, the results obtained in this study indicate that a guanine nucleotide‐binding regulatory protein regulates the polyphosphoinositide breakdown in JURKAT cells by influencing phosphodiesterase activity.