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Nutrients Induce an Increase in Inositol 1,4,5‐Trisphosphate in Soybean Cells: Implication for the Involvement of Phosphoinositide‐Specific Phospholipase C in DNA Synthesis
Author(s) -
Shigaki T.,
Bhattacharyya M. K.
Publication year - 2002
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1055/s-2002-20436
Subject(s) - biology , inositol , diacylglycerol kinase , dna synthesis , phospholipase c , phosphatidylinositol , second messenger system , phosphoinositide phospholipase c , biochemistry , inositol phosphate , phospholipase , phospholipase a2 , signal transduction , dna , receptor , protein kinase c , enzyme
Phosphoinositide‐specific phospholipase C (PI‐PLC) hydrolyzes the membrane lipid phosphatidylinositol 4,5‐bisphosphate (PtdInsP 2 ) to generate 1,2‐diacylglycerol (DAG) and inositol 1,4,5‐trisphosphate (InsP 3 ). Both molecules serve as second messengers to carry out various cellular functions in mammals. In the present study, we demonstrate that many organic and inorganic nutrients cause the elevation of InsP 3 concentrations in cultured soybean cells. This elevation of InsP 3 content is sustained for several hours following treatment with Murashige‐Skoog (MS) inorganic nutrients. Phosphate and calcium are the major components in MS salts responsible for the increase in InsP 3 levels. DNA synthesis, a measure of cell growth, was significantly suppressed by the PI‐PLC‐specific inhibitor 1‐(6‐{[17β‐3‐methoxyestra‐1,3,5(10)‐trien‐17‐yl]amino}hexyl)‐1H‐pyrrole‐2,5‐dione (U‐73122), whereas its near‐identical analogue 1‐(6‐{[17β‐3‐methoxyestra‐1,3,5(10)‐trien‐17‐yl]amino}hexyl)‐2,5‐pyrrolidinedione did not cause any suppression. Activation of PI‐PLC by MS salts increased DNA synthesis and abolished the suppression of DNA synthesis caused by U‐73122. Thus, we conclude that the higher cellular concentration of InsP 3 induced by MS treatment is involved in DNA synthesis.