Hyperpolarization of the plasma membrane potential provokes reorganization of the actin cytoskeleton and increases the stability of adherens junctions in bovine corneal endothelial cells in culture

2009 ◽  
Vol 66 (12) ◽  
pp. 1087-1099 ◽  
Author(s):  
Verónica Nin ◽  
Julio A. Hernández ◽  
Silvia Chifflet
2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Silvia Chifflet ◽  
Julio A. Hernández

The establishment and maintenance of the polarized epithelial phenotype require a characteristic organization of the cytoskeletal components. There are many cellular effectors involved in the regulation of the cytoskeleton of epithelial cells. Recently, modifications in the plasma membrane potential (PMP) have been suggested to participate in the modulation of the cytoskeletal organization of epithelia. Here, we review evidence showing that changes in the PMP of diverse epithelial cells promote characteristic modifications in the cytoskeletal organization, with a focus on the actin cytoskeleton. The molecular paths mediating these effects may include voltage-sensitive integral membrane proteins and/or peripheral proteins sensitive to surface potentials. The voltage dependence of the cytoskeletal organization seems to have implications in several physiological processes, including epithelial wound healing and apoptosis.


2019 ◽  
Vol 33 (9) ◽  
pp. 9785-9796 ◽  
Author(s):  
Takuro Numaga‐Tomita ◽  
Tsukasa Shimauchi ◽  
Sayaka Oda ◽  
Tomohiro Tanaka ◽  
Kazuhiro Nishiyama ◽  
...  

1994 ◽  
Vol 126 (1) ◽  
pp. 247-258 ◽  
Author(s):  
O Ayalon ◽  
H Sabanai ◽  
M G Lampugnani ◽  
E Dejana ◽  
B Geiger

The integrity of the endothelial layer, which lines the entire cavity of the vascular system, depends on tight adhesion of the cells to the underlying basement membrane as well as to each other. It has been previously shown that such interactions occur via membrane receptors that determine the specificity, topology, and mechanical properties of the surface adhesion. Cell-cell junctions between endothelial cells, in culture and in situ, involve both Ca(2+)-dependent and -independent mechanisms that are mediated by distinct adhesion molecules. Ca(2+)-dependent cell-cell adhesion occurs mostly via members of the cadherin family, which locally anchor the microfilament system to the plasma membrane, in adherens junctions. Ca(2+)-independent adhesions were reported to mainly involve members of the Ig superfamily. In this study, we performed three-dimensional microscopic analysis of the relative subcellular distributions of these two endothelial intercellular adhesion systems. We show that cadherins are located at adjacent (usually more apical), yet clearly distinct domains of the lateral plasma membrane, compared to PECAM-1. Moreover, cadherins were first organized in adherens junctions within 2 h after seeding of endothelial cells, forming multiple lateral patches which developed into an extensive belt-like structure over a period of 24 h. PECAM-1 became associated with surface adhesions significantly later and became progressively associated with the cadherin-containing adhesions. Cadherins and PECAM-1 also differed in their detergent extractability, reflecting differences in their mode of association with the cytoskeleton. Moreover, the two adhesion systems could be differentially modulated since short treatment with the Ca2+ chelator EGTA, disrupted the cadherin junctions leaving PECAM-1 apparently intact. These results confirm that endothelial cells possess distinct intercellular contact mechanisms that differ in their spatial and temporal organization as well as in their functional properties.


1996 ◽  
Vol 314 (2) ◽  
pp. 595-601 ◽  
Author(s):  
Fabienne DEFRISE-QUERTAIN ◽  
Chantal FRASER-L'HOSTIS ◽  
Danièle CORAL ◽  
Jacques DESHUSSES

The characteristics of the plasma-membrane potential of procyclic and bloodstream forms of Trypanosoma brucei brucei (cultured cells) were investigated using the fluorescent anionic probe bisoxonol. Observation of a stable and representative plasma-membrane potential in the resting state required careful washing, centrifugation and maintenance of the cells at room temperature before measurement. Bloodstream forms were more prone to depolarization during washing at 4 °C than procyclic cells. The higher fluorescence observed in the presence of long slender cells than in the presence of procyclic cells shows that the plasma-membrane potential is more negative in the insect form. Healthy dilute cells can sustain their plasma-membrane potential for hours in the presence of external glucose. The presence of a high K+ concentration in the medium did not promote by itself the depolarization of either type of cell. Study of bisoxonol fluorescence as a function of time allowed us to follow the kinetics of the action of metabolic inhibitors in the presence of various ions. o-Vanadate (1 mM) was found to depolarize bloodstream-form cells rapidly but only in a phosphate-free NaCl buffer. Omeprazole and strophanthidin also specifically depolarized bloodstream-form trypanosomes. However, NN´-dicyclohexylcarbodi-imide depolarized both types of cell, but more rapidly for bloodstream-form cells. Bloodstream-form trypanosomes appear to use mainly a vanadate-sensitive Na+ pump to maintain their Na+-diffusion gradient. However, most of the ATPase inhibitors tested had little or no effect on the plasma-membrane potential of procyclics suggesting that this form of trypanosome may rely on several regulation mechanisms.


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