Phosphoinositides and phosphatidic acid regulate pollen tube growth and reorientation through modulation of [Ca2+]c and membrane secretion
The maintenance of a calcium gradient and vesicle secretion in the apex of pollen tubes is essential for growth. It is shown here that phosphatidylinositol-4,5-bisphosphate (PIP2) and D-myo-inositol-1,4,5-trisphosphate (IP3), together with phosphatidic acid (PA), play a vital role in the regulation...
| Veröffentlicht in: | Journal of experimental botany. - 1985. - 56(2005), 416 vom: 14. Juni, Seite 1665-74 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2005
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| Zugriff auf das übergeordnete Werk: | Journal of experimental botany |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Phosphatidic Acids Phosphatidylinositol 4,5-Diphosphate Inositol 1,4,5-Trisphosphate 85166-31-0 Calcium SY7Q814VUP |
| Zusammenfassung: | The maintenance of a calcium gradient and vesicle secretion in the apex of pollen tubes is essential for growth. It is shown here that phosphatidylinositol-4,5-bisphosphate (PIP2) and D-myo-inositol-1,4,5-trisphosphate (IP3), together with phosphatidic acid (PA), play a vital role in the regulation of these processes. Changes in the intracellular concentration of both PIP2 and IP3 (induced by photolysis of caged-probes), modified growth and caused reorientation of the growth axis. However, measurements of cytosolic free calcium ([Ca2+]c) and apical secretion revealed significant differences between the photo-release of PIP2 or IP3. When released in the first 50 mum of the pollen tube, PIP2 led to transient growth perturbation, [Ca2+]c increases, and inhibition of apical secretion. By contrast, a concentration of IP3 which caused a [Ca2+]c transient of similar magnitude, stimulated apical secretion and caused severe growth perturbation. Furthermore, the [Ca2+]c transient induced by IP3 was spatially different causing a pronounced elevation in the sub-apical region. These observations suggest different targets for the two phosphoinositides. One of the targets is suggested to be PA, a product of PIP2 hydrolysis via phospholipase C (PLC) or phospholipase D (PLD) activity. It was found that antagonists of PA accumulation (e.g. butan-1-ol) and inhibitors of PLC and PLD reversibly halted polarity. Reduction of PA levels caused the dissipation of the [Ca2+]c gradient and inhibited apical plasma membrane recycling. It was also found to cause abolition of the apical zonation. These data suggest that phosphoinositides and phospholipids regulate tip growth through a multiple pathway system involving regulation of [Ca2+]c levels, endo/exocytosis, and vesicular trafficking |
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| Beschreibung: | Date Completed 07.07.2005 Date Revised 10.03.2022 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1460-2431 |