Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10748246 | Biochemical and Biophysical Research Communications | 2016 | 30 Pages |
Abstract
Salt stress is a major environmental stress for plants, causing hyperosmotic, ionic and drought-like stresses. Plasma membrane intrinsic protein 2;1 (PIP2;1), which forms a water channel that regulates water flux thorough the plasma membrane (PM), is constitutively trafficked between the PM and the trans-Golgi network (TGN) in Arabidopsis thaliana. Salt stress is known to relocalize PIP2;1 to intracellular compartments, probably to decrease the water permeability of the root. However, the destination of internalized PIP2;1 and the mechanism by which PIP2;1 is internalized remain unclear. Here, we examined the effects of salt stress and inhibitors of endocytosis on the intracellular localization of green fluorescent protein-fused PIP2;1 (GFP-PIP2;1) in Arabidopsis thaliana root epidermal cells. Salt stress decreased the fluorescence of GFP-PIP2;1Â at the PM and increased it in the vacuolar lumen as shown by staining of the vacuolar membrane. The internalization of PIP2;1 was suppressed by an inhibitor of clathrin-mediated endocytosis and by inhibitors of two kinases that appear to have roles in salt stress, phosphatidylinositol 3-kinase (PI3K) and phosphatidylinositol 4-kinase (PI4K). Inhibiting PI4K suppressed the salt-induced endocytosis of GFP-PIP2;1Â at the PM, whereas inhibiting PI3K suppressed the trafficking of GFP-PIP2;1 after its internalization. These results suggest that salt stress induces the internalization of PIP2;1 from the PM to the vacuolar lumen, and that these processes are dependent on clathrin, PI3K and PI4K.
Keywords
PI3KFIRBFATGNCIEPtdInsGFPPI4KPAOCLSMDMSOMurashige and SkoogArabidopsisCMEEndocytosisaquaporinClathrin-mediated endocytosisPhenylarsine oxidebrefeldin ASalt stressDimethyl sulfoxideTrans-Golgi networkPlasma membranephosphatidylinositolPhosphatidylinositol 3-kinasephosphatidylinositol 4-kinasePhosphoinositideprevacuolar compartmentConfocal laser scanning microscopeplasma membrane intrinsic proteingreen fluorescent proteinPVCPiPClathrin
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Authors
Masamichi Ueda, Nobuhiro Tsutsumi, Masaru Fujimoto,