Article

Changes in plasma membrane surface potential of PC12 cells as measured by Kelvin probe force microscopy.

Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan.
PLoS ONE (Impact Factor: 3.73). 01/2012; 7(4):e33849. DOI: 10.1371/journal.pone.0033849
Source: PubMed

ABSTRACT The plasma membrane of a cell not only works as a physical barrier but also mediates the signal relay between the extracellular milieu and the cell interior. Various stimulants may cause the redistribution of molecules, like lipids, proteins, and polysaccharides, on the plasma membrane and change the surface potential (Φ(s)). In this study, the Φ(s)s of PC12 cell plasma membranes were measured by atomic force microscopy in Kelvin probe mode (KPFM). The skewness values of the Φ(s)s distribution histogram were found to be mostly negative, and the incorporation of negatively charged phosphatidylserine shifted the average skewness values to positive. After being treated with H(2)O(2), dopamine, or Zn(2+), phosphatidylserine was found to be translocated to the membrane outer leaflet and the averaged skewness values were changed to positive values. These results demonstrated that KPFM can be used to monitor cell physiology status in response to various stimulants with high spatial resolution.

0 Bookmarks
 · 
78 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Membranes with simple lipid composition exhibit complex phase behavior. Ordered and disordered liquid phases can coexist in cholesterol-containing membranes with lipid compositions resembling biological membranes and at physiological temperatures. Research during the last years suggests that these lipid domains play a role in the organization of biological membranes. Understanding the principles that govern the formation and stability of lipid domains is of great importance to build a model that properly describes membrane structure and function. In this review, we describe the current knowledge of the chemical and physical basis of lipid domains and its application to biological membranes.
    FEBS letters 05/2010; 584(9):1653-8. · 3.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Over the last 25 years one of us (WKS) has been investigating physical properties of lipid bilayer membranes. In 1991 a group led by WKS was organized into the Laboratory of Structure and Dynamics of Biological Membranes, the effective member of which is AW. Using mainly the electron paramagnetic resonance (EPR) spin-labeling method, we obtained unexpected results, which are significant for the better understanding of the functioning of biological membranes. We have developed a new pulse EPR spin-labeling method for the detection of membrane domains and evaluation of lipid exchange rates. This review will be focused on our main results which can be summarized as follows: (1) Unsaturation of alkyl chains greatly reduces the ordering and rigidifying effects of cholesterol although the unsaturation alone gives only minor fluidizing effects, as observed by order and reorientational motion, and rather significant rigidifying effects, as observed by translational motion of probe molecules; (2) Fluid-phase model membranes and cell plasma membranes are not barriers to oxygen and nitric oxide transport; (3) Polar carotenoids can regulate membrane fluidity in a way similar to cholesterol; (4) Formation of effective hydrophobic barriers to the permeation of small polar molecules across membranes requires alkyl chain unsaturation and/or the presence of cholesterol; (5) Fluid-phase micro-immiscibility takes place in cis-unsaturated phosphatidylcholine-cholesterol membranes and induces the formation of cholesterol-rich domains; (6) In membranes containing high concentrations of transmembrane proteins a new lipid domain is formed, with lipids trapped within aggregates of proteins, in which the lipid dynamics is diminished to the level of gel-phase.
    Acta biochimica Polonica 02/2000; 47(3):613-25. · 1.19 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Phosphatidylserine (PS) is the most abundant negatively charged phospholipid in eukaryotic membranes. PS directs the binding of proteins that bear C2 or gamma-carboxyglutamic domains and contributes to the electrostatic association of polycationic ligands with cellular membranes. Rather than being evenly distributed, PS is found preferentially in the inner leaflet of the plasma membrane and in endocytic membranes. The loss of PS asymmetry is an early indicator of apoptosis and serves as a signal to initiate blood clotting. This review discusses the determinants and functional implications of the subcellular distribution and membrane topology of PS.
    Annual Review of Biophysics 02/2010; 39:407-27. · 12.63 Impact Factor

Full-text (3 Sources)

View
14 Downloads
Available from
May 27, 2014