scholarly journals Ectopic expression ofArabidopsis thalianaplasma membrane intrinsic protein 2 aquaporins in lily pollen increases the plasma membrane water permeability of grain but not of tube protoplasts

2008 ◽  
Vol 180 (4) ◽  
pp. 787-797 ◽  
Author(s):  
Aniela Sommer ◽  
Birgit Geist ◽  
Olivier Da Ines ◽  
Renate Gehwolf ◽  
Anton R. Schäffner ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Water Permeability ◽  
Ectopic Expression ◽  
Intrinsic Protein ◽  
Lily Pollen

Ectopic expression of a rice plasma membrane intrinsic protein (OsPIP1;3) promotes plant growth and water uptake

2020 ◽  
Vol 102 (4) ◽  
pp. 779-796 ◽  
Author(s):  
Siyu Liu ◽  
Tatsuya Fukumoto ◽  
Patrizia Gena ◽  
Peng Feng ◽  
Qi Sun ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Plant Growth ◽  
Water Uptake ◽  
Ectopic Expression ◽  
Plasma Membrane Intrinsic Protein ◽  
Intrinsic Protein

scholarly journals Methylation of aquaporins in plant plasma membrane

2006 ◽  
Vol 400 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Véronique Santoni ◽  
Lionel Verdoucq ◽  
Nicolas Sommerer ◽  
Joëlle Vinh ◽  
Delphine Pflieger ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Water Permeability ◽  
Plant Root ◽  
Ectopic Expression ◽  
Regulatory Mechanisms ◽  
Wild Type ◽  
Post Translational Modification ◽  
Suspension Cells ◽  
Plant Plasma Membrane

A thorough analysis, using MS, of aquaporins expressed in plant root PM (plasma membrane) was performed, with the objective of revealing novel post-translational regulations. Here we show that the N-terminal tail of PIP (PM intrinsic protein) aquaporins can exhibit multiple modifications and is differentially processed between members of the PIP1 and PIP2 subclasses. Thus the initiating methionine was acetylated or cleaved in native PIP1 and PIP2 isoforms respectively. In addition, several residues were detected to be methylated in PIP2 aquaporins. Lys3 and Glu6 of PIP2;1, one of the most abundant aquaporins in the PM, occurred as di- and mono-methylated residues respectively. Ectopic expression in Arabidopsis suspension cells of PIP2;1, either wild-type or with altered methylation sites, revealed an interplay between methylation at the two sites. Measurements of water transport in PM vesicles purified from these cells suggested that PIP2;1 methylation does not interfere with the aquaporin intrinsic water permeability. In conclusion, the present study identifies methylation as a novel post-translational modification of aquaporins, and even plant membrane proteins, and may represent a critical advance towards the identification of new regulatory mechanisms of membrane transport.

scholarly journals Short-term control of maize cell and root water permeability through plasma membrane aquaporin isoforms

2011 ◽  
Vol 35 (1) ◽  
pp. 185-198 ◽  
Author(s):  
CHARLES HACHEZ ◽  
DMITRY VESELOV ◽  
QING YE ◽  
HAGEN REINHARDT ◽  
THORSTEN KNIPFER ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Water Permeability ◽  
Short Term ◽  
Maize Cell

scholarly journals The plasma membrane transporter SLC5A8 suppresses tumour progression through depletion of survivin without involving its transport function

2013 ◽  
Vol 450 (1) ◽  
pp. 169-178 ◽  
Author(s):  
Veena Coothankandaswamy ◽  
Selvakumar Elangovan ◽  
Nagendra Singh ◽  
Puttur D. Prasad ◽  
Muthusamy Thangaraju ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cancer Cells ◽  
Histone Deacetylase Inhibitors ◽  
Tumour Progression ◽  
Ectopic Expression ◽  
Membrane Transporter ◽  
Transport Function ◽  
Plasma Membrane Transporter

SLC5A8 (solute carrier gene family 5A, member 8) is a sodium-coupled transporter for monocarboxylates. Among its substrates are the HDAC (histone deacetylase) inhibitors butyrate, propionate and pyruvate. Expression of SLC5A8 is silenced in cancers via DNA methylation, and ectopic expression of SLC5A8 in cancer cells induces apoptosis in the presence of its substrates that are HDAC inhibitors. In the present study we show that ectopic expression of SLC5A8 in cancer cells translocates the anti-apoptotic protein survivin to the plasma membrane through protein–protein interaction resulting in depletion of nuclear survivin and also decreases cellular levels of survivin through inhibition of transcription. These SLC5A8-induced changes in the location and levels of survivin result in cell-cycle arrest, disruption of the chromosome passenger complex involved in mitosis, induction of apoptosis and enhancement in chemosensitivity. These effects are seen independently of the transport function of SLC5A8 and histone acetylation status of the cell; in the presence of pyruvate, a SLC5A8 substrate and also an HDAC inhibitor, these effects are amplified. Ectopic expression of SLC5A8 in the breast cancer cell line MB231 inhibits the ability of cells to form colonies in vitro and to form tumours in mouse xenografts in vivo. The suppression of survivin transcription occurs independently of HDAC inhibition, and the underlying mechanism is associated with decreased phosphorylation of STAT3 (signal transducer and activator of transcription 3). The observed effects are specific for survivin with no apparent changes in expression of other inhibitor-of-apoptosis proteins. The present study unravels a novel, hitherto unrecognized, mechanism for the tumour-suppressive role of a plasma membrane transporter independent of its transport function.

scholarly journals MAL, an Integral Element of the Apical Sorting Machinery, Is an Itinerant Protein That Cycles between the Trans-Golgi Network and the Plasma Membrane

1999 ◽  
Vol 10 (10) ◽  
pp. 3435-3447 ◽  
Author(s):  
Rosa Puertollano ◽  
Miguel A. Alonso
Keyword(s):  
Plasma Membrane ◽  
Protein Transport ◽  
Ectopic Expression ◽  
Integral Membrane Protein ◽  
Membrane Microdomains ◽  
Surface Binding ◽  
Flag Epitope ◽  
Trans Golgi Network ◽  
Endosomal Acidification ◽  
Golgi Network

The MAL proteolipid is a nonglycosylated integral membrane protein found in glycolipid-enriched membrane microdomains. In polarized epithelial Madin-Darby canine kidney cells, MAL is necessary for normal apical transport and accurate sorting of the influenza virus hemagglutinin. MAL is thus part of the integral machinery for glycolipid-enriched membrane–mediated apical transport. At steady state, MAL is predominantly located in perinuclear vesicles that probably arise from the trans-Golgi network (TGN). To act on membrane traffic and to prevent their accumulation in the target compartment, integral membrane elements of the protein-sorting machinery should be itinerant proteins that cycle between the donor and target compartments. To establish whether MAL is an itinerant protein, we engineered the last extracellular loop of MAL by insertion of sequences containing the FLAG epitope or with sequences containing residues that became O-glycosylated within the cells or that displayed biotinylatable groups. The ectopic expression of these modified MAL proteins allowed us to investigate the surface expression of MAL and its movement through different compartments after internalization with the use of a combination of assays, including surface biotinylation, surface binding of anti-FLAG antibodies, neuraminidase sensitivity, and drug treatments. Immunofluorescence and flow cytometric analyses indicated that, in addition to its Golgi localization, MAL was also expressed on the cell surface, from which it was rapidly internalized. This retrieval implies transport through the endosomal pathway and requires endosomal acidification, because it can be inhibited by drugs such as chloroquine, monensin, and NH4Cl. Resialylation experiments of surface MAL treated with neuraminidase indicated that ∼30% of the internalized MAL molecules were delivered to the TGN, probably to start a new cycle of cargo transport. Together, these observations suggest that, as predicted for integral membrane members of the late protein transport machinery, MAL is an itinerant protein cycling between the TGN and the plasma membrane.

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