Subcellular Localization of Inorganic Ions in Plant Cells

Phosphatidic acid (PA) is involved in the regulation of plant growth and development, as well as responses to various environmental stimuli. Several PA targets in plant cells were identified, including two SNF1-related protein kinases 2 (SnRK2s), SnRK2.10 and SnRK2.4, which are not activated by abscisic acid (ABA). Here, we investigated the effects of PA on various elements of ABA-non-activated SnRK2 signaling. PA 16:0/18:1 was found to modulate the SnRK2 structure and the phosphorylation of some SnRK2 targets. Conversely, phosphorylation by the ABA-non-activated SnRK2s, of one of such targets, dehydrin Early Responsive to Dehydration 14 (ERD14), affects its interaction with PA and subcellular localization. Moreover, PA 16:0/18:1 modulates the activity and/or localization of negative regulators of the ABA-non-activated SnRK2s, not only of the ABA insensitive 1 (ABI1) phosphatase, which was identified earlier, but also of another protein phosphatase 2C, PP2CA. The activity of both phosphatases was inhibited by about 50% in the presence of 50 μM PA. PA 16:0/18:1 also impacts the phosphorylation and subcellular localization of SnRK2-interacting calcium sensor, known to inhibit SnRK2 activity in a calcium-dependent manner. Thus, PA was found to regulate ABA-non-activated SnRK2 signaling at several levels: the activity, phosphorylation status and/or localization of SnRK2 cellular partners.

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Subcellular localization and possible functions of acid ?-glycerophosphatases and naphthol esterases in plant cells

Planta ◽

10.1007/bf00386980 ◽

1969 ◽

Vol 89 (2) ◽

pp. 126-135 ◽

Cited By ~ 38

Author(s):

P. B. Gahan ◽

J. McLean

Keyword(s):

Subcellular Localization ◽

Plant Cells

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Embedding of unfixed plant material in water-soluble resin: A simple preparation method for elemental analysis by ESI and EELS techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161424 ◽

1990 ◽

Vol 48 (3) ◽

pp. 772-773

Author(s):

Heiner Lehmann ◽

Ulrike Kunz

Keyword(s):

Preparation Method ◽

Plant Cells ◽

Inorganic Ions ◽

Living Cells ◽

Water Soluble ◽

Preparation Technique ◽

Chemical Fixation ◽

Electron Spectroscopic Imaging ◽

Simple Preparation ◽

Electron Energy Loss

The localization of elements in cells and tissues by electron spectroscopic imaging (ESI) or electron energy loss spectroscopy (EELS) can be realized only in very thin specimens in order to avoid multiple scattering of the electrons. Therefore the biological material has to be cut in thin 30 nm sections.The commonly used preparation procedure is a hydrous chemical fixation followed by dehydration, embedding in hydrophobic resin and ultrathin sectioning. The disadvantage of this procedure is the loss and/or dislocation of inorganic ions and other water-soluble substances. To overcome these difficulties the preferable preparation method is cryofixation in combination with cryosubstitution, but this is a very expensive and time-wasting procedure.Meanwhile, we established a more simplified preparation technique, which shows reasonable results on plant cells without large central vacuoles: The living cells were directly put into freshly mixed Nanoplast FB 101, a water-soluble melanine resin, and stored for 24 h at 20° C in a silca gel containing exsiccator.

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