Osmotically evoked shrinking of guard-cell protoplasts causes vesicular retrieval of plasma membrane into the cytoplasm

Kubitscheck, Ulrich; Homann, Ulrike; Thiel, Gerhard

doi:10.1007/pl00008151

Cited by 66 publications

(42 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous work with guard cell protoplasts using a membrane-specific fluorescent dye similar to the one used in this study showed internalization of plasma membrane and vesicle formation in response to osmotic solutions (Kubitscheck et al, 2000). The lack of turgor pressure in protoplasts makes it difficult to extrapolate those findings from protoplasts to intact guard cells, and there are several notable differences between our results and those with protoplasts.…”

Section: Discussioncontrasting

confidence: 74%

“…Furthermore, it has been shown that the cross-sectional shape of guard cells is nearly circular at high turgor pressures, but becomes more flattened as they lose turgor (Raschke, 1979). This lends credibility to the first solution because flattening could produce changes in volume while maintaining a constant surface area.The problem of how guard cells maintain the integrity of the plasma membrane during volume changes has been addressed using osmotically induced changes in the volume of guard cell protoplasts (Homann, 1998;Kubitscheck et al, 2000). Those studies showed that vesicles were internalized 1 This work was supported by the National Science Foundation (grant no.…”

mentioning

confidence: 99%

“…The problem of how guard cells maintain the integrity of the plasma membrane during volume changes has been addressed using osmotically induced changes in the volume of guard cell protoplasts (Homann, 1998;Kubitscheck et al, 2000). Those studies showed that vesicles were internalized and retrieved to the plasma membrane as protoplast volume changed.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Changes in Surface Area of Intact Guard Cells Are Correlated with Membrane Internalization

2003

View full text Add to dashboard Cite

Guard cells must maintain the integrity of the plasma membrane as they undergo large, rapid changes in volume. It has been assumed that changes in volume are accompanied by changes in surface area, but mechanisms for regulating plasma membrane surface area have not been identified in intact guard cells, and the extent to which surface area of the guard cells changes with volume has never been determined. The alternative hypothesis-that surface area remains approximately constant because of changes in shape-has not been investigated. To address these questions, we determined surface area for intact guard cells of Vicia faba as they underwent changes in volume in response to changes in the external osmotic potential. We also estimated membrane internalization for these cells. Epidermal peels were subjected to external solutions of varying osmotic potential to shrink and swell the guard cells. A membrane-specific fluorescent dye was used to identify the plasma membrane, and confocal microscopy was used to acquire a series of optical paradermal sections of the guard cell pair at each osmotic potential. Solid digital objects representing the guard cells were created from the membrane outlines identified in these paradermal sections, and surface area, volume, and various linear dimensions were determined for these solid objects. Surface area decreased by as much as 40% when external osmotic potential was increased from 0 to 1.5 MPa, and surface area varied linearly with volume. Membrane internalization was approximated by determining the amount of the fluorescence in the cell's interior. This value was shown to increase approximately linearly with decreases in the cell's surface area. The changes in surface area, volume, and membrane internalization were reversible when the guard cells were returned to a buffer solution with an osmotic potential of approximately zero. The data show that intact guard cells undergo changes in surface area that are too large to be accommodated by plasma membrane stretching and shrinkage and suggest that membrane is reversibly internalized to maintain cell integrity.Guard cells regulate stomatal pore size to allow CO 2 uptake while controlling water loss. To accomplish this, they respond to environmental factors such as light and CO 2 concentration and to chemical signals such as ABA, which may originate in other parts of the plant. Guard cells respond to these factors by regulating ion fluxes across the plasma membrane, and the resulting movement of water causes changes in cell volume, turgor pressure, and shape, leading to changes in the pore aperture. The changes in guard cell turgor pressure and volume caused by these processes can be quite large. In Vicia faba, guard cell turgor pressure has been shown to vary between 1.0 and 4.0 MPa (Franks et al., 1998(Franks et al., , 2001) as stomata go from closed to wide open, and volume has been shown to change by as much as 40% (Raschke and Dickerson, 1973;Franks et al., 2001). These changes can occur over a time period of minutes.An often-un...

show abstract

Section: Discussioncontrasting

confidence: 74%

mentioning

confidence: 99%

See 1 more Smart Citation

Changes in Surface Area of Intact Guard Cells Are Correlated with Membrane Internalization

2003

View full text Add to dashboard Cite

show abstract

“…These changes in capacitance are consistent in size with the predicted vesicle dimensions derived from ultrastructural studies (Picton and Steer, 1983;Phillips et al, 1988) and from imaging studies using fluorescent styryl dyes to label internalized membrane . Factors shown to affect vesicle traffic in plants include cytosol-free Ca 2þ concentration ([Ca 2þ ] i ), guanosine nucleotides (Homann and Tester, 1997;Carroll et al, 1998), and osmotic changes (Kubitscheck et al, 2000). Furthermore, evidence for [Ca 2þ ] i -dependent and -independent exocytotic pathways underscores the complexity of secretory processing that must occur in parallel within individual cells (Homann and Tester, 1997;Sutter et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Selective Mobility and Sensitivity to SNAREs Is Exhibited by theArabidopsisKAT1 K+ Channel at the Plasma Membrane

et al. 2006

View full text Add to dashboard Cite

Recent findings indicate that proteins in the SNARE superfamily are essential for cell signaling, in addition to facilitating vesicle traffic in plant cell homeostasis, growth, and development. We previously identified SNAREs SYP121/Syr1 from tobacco (Nicotiana tabacum) and the Arabidopsis thaliana homolog SYP121 associated with abscisic acid and drought stress. Disrupting tobacco SYP121 function by expressing a dominant-negative Sp2 fragment had severe effects on growth, development, and traffic to the plasma membrane, and it blocked K þ and Cl ÿ channel responses to abscisic acid in guard cells. These observations raise questions about SNARE control in exocytosis and endocytosis of ion channel proteins and their organization within the plane of the membrane. We have used a dual, in vivo tagging strategy with a photoactivatable green fluorescent protein and externally exposed hemagglutinin epitopes to monitor the distribution and trafficking dynamics of the KAT1 K þ channel transiently expressed in tobacco leaves. KAT1 is localized to the plasma membrane within positionally stable microdomains of ;0.5 mm in diameter; delivery of the K þ channel, but not of the PMA2 H þ -ATPase, to the plasma membrane is suppressed by Sp2 fragments of tobacco and Arabidopsis SYP121, and Sp2 expression leads to profound changes in KAT1 distribution and mobility within the plane of the plasma membrane. These results offer direct evidence for SNARE-mediated traffic of the K þ channel and a role in its distribution within subdomains of the plasma membrane, and they implicate a role for SNAREs in positional anchoring of the K þ channel protein.

show abstract

“…The mechanism by which antibodies may enter into a living cell through the plasma membrane is largely unknown. In plant protoplasts, it has been shown the occurrence of constitutive endocytosis (Kubitscheck et al 2000), strongly enhanced by an increase of the osmotic pressure. But depolymerising actin microfilaments with latrunculin B, known to inhibit endocytosis, did not prevent antibody uptake in sunflower protoplasts (result not shown).…”

Section: Discussionmentioning

confidence: 99%

A new tool for plant cell biology: in vivo antibody uptake in plant protoplasts

Brière

Barthou

2004

Plant Cell Rep

View full text Add to dashboard Cite

We report on the in vivo uptake of antibodies into plant protoplasts. It is shown by immunofluorescence that when protoplasts of sunflower, Arabidopsis or tobacco were incubated in vivo with an antibody, this antibody was detected in the cytoplasm and/or the nucleus, depending on the location of the target protein. Furthermore, when protoplasts were cultured in the presence of antibodies specific effects were observed. Incubation with antibodies raised against p34 cdc2 led to a strong inhibition of the division rate and a decrease of the average DNA content of protoplasts. With antibodies against HaWLIM1, a LIM domain protein of the CRP type, a negative effect on actin organization was observed. It is concluded that antibodies can penetrate in vivo into plant protoplasts and thus may be used as powerful tools for the study of protein function.

show abstract

Osmotically evoked shrinking of guard-cell protoplasts causes vesicular retrieval of plasma membrane into the cytoplasm

Cited by 66 publications

References 21 publications

Changes in Surface Area of Intact Guard Cells Are Correlated with Membrane Internalization

Changes in Surface Area of Intact Guard Cells Are Correlated with Membrane Internalization

Selective Mobility and Sensitivity to SNAREs Is Exhibited by theArabidopsisKAT1 K+ Channel at the Plasma Membrane

A new tool for plant cell biology: in vivo antibody uptake in plant protoplasts

Contact Info

Product

Resources

About