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Inositol 1,3,4,5‐tetrakisphosphate increases the duration of the inositol 1,4,5‐trisphosphate‐mediated Ca 2+ transient
Author(s) -
Joseph Suresh K.,
Hansen Carl A.,
Williamson John R.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81203-6
Subject(s) - inositol , chemistry , transient (computer programming) , inositol phosphate , biochemistry , biophysics , biology , receptor , computer science , operating system
The effect of Ins 1,3,4,5‐P 4 on the intracellular Ca 2+ mobilization produced by Ins 1,4,5‐P, has been examined in permeabilized hepatocytes. Ins 1,3,4,5‐P 4 did not affect the magnitude of the Ins 1,4,5‐P 3 ‐mediated Ca 2+ release but did inhibit re‐accumulation of the released Ca 2+ back into intracellular stores. This effect was not mimicked by Ins 1,3,4‐P 3 . In hepatocytes, the re‐uptake phase of the response results from Ins 1,4,5‐P 3 hydrolysis. Measurements using labeled substrates indicate that Ins 1,3,4,5‐P 4 inhibits the hydrolysis of Ins 1,4,5‐P 3 and vice versa. Since the removal of the 5‐phosphate on Ins 1,4,5‐P 3 and Ins 1,3,4,5‐P 4 is a common step in the disposal of both compounds, it is suggested that one of the biological effects of Ins 1,3,4,5‐P 4 may be to slow hydrolysis of Ins 1,4,5‐P 3 and thereby prolong the duration of a Ca 2+ transient.