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Identification of a new polyphosphoinositide in plants, phosphatidylinositol 5-monophosphate (PtdIns5P), and its accumulation upon osmotic stress

Identification of a new polyphosphoinositide in plants, phosphatidylinositol 5-monophosphate (PtdIns5P), and its accumulation upon osmotic stress
Identification of a new polyphosphoinositide in plants, phosphatidylinositol 5-monophosphate (PtdIns5P), and its accumulation upon osmotic stress
Polyphosphoinositides play an important role in membrane trafficking and cell signalling. In plants, two PtdInsP isomers have been described, PtdIns3P and PtdIns4P. Here we report the identification of a third, PtdIns5P. Evidence is based on the conversion of the endogenous PtdInsP pool into PtdIns(4,5)P(2) by a specific PtdIns5P 4-OH kinase, and on in vivo (32)P-labelling studies coupled to HPLC head-group analysis. In Chlamydomonas, 3-8% of the PtdInsP pool was PtdIns5P, 10-15% was PtdIns3P and the rest was PtdIns4P. In seedlings of Vicia faba and suspension-cultured tomato cells, the level of PtdIns5P was about 18%, indicating that PtdIns5P is a general plant lipid that represents a significant proportion of the PtdInsP pool. Activating phospholipase C (PLC) signalling in Chlamydomonas cells with mastoparan increased the turnover of PtdIns(4,5)P(2) at the cost of PtdIns4P, but did not affect the level of PtdIns5P. This indicates that PtdIns(4,5)P(2) is synthesized from PtdIns4P rather than from PtdIns5P during PLC signalling. However, when cells were subjected to hyperosmotic stress, PtdIns5P levels rapidly increased, suggesting a role in osmotic-stress signalling. The potential pathways of PtdIns5P formation are discussed.
Animals Cell Line Chlamydomonas/cytology/drug effects/enzymology/metabolism Enzyme Activation/drug effects Fabaceae/cytology/metabolism Intercellular Signaling Peptides and Proteins Isomerism Solanum lycopersicum/cytology/metabolism Osmotic Pressure Peptides Phosphatidylinositol Phosphates/*isolation & purification/*metabolism Plant Cells Plants/drug effects/enzymology/*metabolism Rats Type C Phospholipases/metabolism Wasp Venoms/pharmacology
0264-6021
491-498
Meijer, H. J.
937eefee-6848-476e-bea1-8ed244c1ad46
Berrie, C. P.
733c9520-9a05-4e12-8cb1-48cbe5242a97
Iurisci, C.
ed9176b9-c06c-4ba9-ad1d-69ee70c11e12
Divecha, N.
5c2ad0f8-4ce7-405f-8a15-2fc4ab96d787
Musgrave, A.
726d2402-4fa0-44a6-9028-c25c6164acf6
Munnik, T.
3f33c9a2-167b-400a-a9ee-7cd7ca53089a
Meijer, H. J.
937eefee-6848-476e-bea1-8ed244c1ad46
Berrie, C. P.
733c9520-9a05-4e12-8cb1-48cbe5242a97
Iurisci, C.
ed9176b9-c06c-4ba9-ad1d-69ee70c11e12
Divecha, N.
5c2ad0f8-4ce7-405f-8a15-2fc4ab96d787
Musgrave, A.
726d2402-4fa0-44a6-9028-c25c6164acf6
Munnik, T.
3f33c9a2-167b-400a-a9ee-7cd7ca53089a

Meijer, H. J., Berrie, C. P., Iurisci, C., Divecha, N., Musgrave, A. and Munnik, T. (2001) Identification of a new polyphosphoinositide in plants, phosphatidylinositol 5-monophosphate (PtdIns5P), and its accumulation upon osmotic stress. Biochemical Journal, 360 (Pt 2), 491-498. (doi:10.1042/0264-6021:3600491).

Record type: Article

Abstract

Polyphosphoinositides play an important role in membrane trafficking and cell signalling. In plants, two PtdInsP isomers have been described, PtdIns3P and PtdIns4P. Here we report the identification of a third, PtdIns5P. Evidence is based on the conversion of the endogenous PtdInsP pool into PtdIns(4,5)P(2) by a specific PtdIns5P 4-OH kinase, and on in vivo (32)P-labelling studies coupled to HPLC head-group analysis. In Chlamydomonas, 3-8% of the PtdInsP pool was PtdIns5P, 10-15% was PtdIns3P and the rest was PtdIns4P. In seedlings of Vicia faba and suspension-cultured tomato cells, the level of PtdIns5P was about 18%, indicating that PtdIns5P is a general plant lipid that represents a significant proportion of the PtdInsP pool. Activating phospholipase C (PLC) signalling in Chlamydomonas cells with mastoparan increased the turnover of PtdIns(4,5)P(2) at the cost of PtdIns4P, but did not affect the level of PtdIns5P. This indicates that PtdIns(4,5)P(2) is synthesized from PtdIns4P rather than from PtdIns5P during PLC signalling. However, when cells were subjected to hyperosmotic stress, PtdIns5P levels rapidly increased, suggesting a role in osmotic-stress signalling. The potential pathways of PtdIns5P formation are discussed.

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More information

Published date: September 2001
Additional Information: Meijer, H J Berrie, C P Iurisci, C Divecha, N Musgrave, A Munnik, T eng E.0841/TI_/Telethon/Italy Research Support, Non-U.S. Gov't England 2001/11/22 Biochem J. 2001 Dec 1;360(Pt 2):491-8. doi: 10.1042/0264-6021:3600491.
Keywords: Animals Cell Line Chlamydomonas/cytology/drug effects/enzymology/metabolism Enzyme Activation/drug effects Fabaceae/cytology/metabolism Intercellular Signaling Peptides and Proteins Isomerism Solanum lycopersicum/cytology/metabolism Osmotic Pressure Peptides Phosphatidylinositol Phosphates/*isolation & purification/*metabolism Plant Cells Plants/drug effects/enzymology/*metabolism Rats Type C Phospholipases/metabolism Wasp Venoms/pharmacology

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Local EPrints ID: 479788
URI: http://eprints.soton.ac.uk/id/eprint/479788
ISSN: 0264-6021
PURE UUID: 4613f3db-b564-45ae-b740-f0743e841551

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Date deposited: 26 Jul 2023 17:03
Last modified: 17 Mar 2024 03:00

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Contributors

Author: H. J. Meijer
Author: C. P. Berrie
Author: C. Iurisci
Author: N. Divecha
Author: A. Musgrave
Author: T. Munnik

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