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Stimulation of phosphatidylinositol 4‐phosphate phosphorylation in human placenta membranes by GTPγS
Author(s) -
Urumow T.,
Wieland O.H.
Publication year - 1986
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(86)81499-5
Subject(s) - phosphatidylinositol , phosphorylation , stimulation , gtp' , membrane , chemistry , phosphate , microbiology and biotechnology , biochemistry , endocrinology , biology , enzyme
In human placenta membranes the rate limiting enzyme for PIP 2 formation from PI is PIP kinase. GTPγS is shown to activate PIP kinase by increasing V max of the enzyme. It is suggested that a guanine nucleotide regulatory protein is involved in the activation of PIP kinase although coupling with a specific receptor is not yet known. Since PIP 2 is the preferred substrate of phospholipase C, the possibility exists that an increase of PIP 2 due to activation of PIP kinase leads to an enhancement of phospholipase C activity and hence to an increased production of IP 3 and DAG.