Electrostatic Properties of Membrane Lipids Coupled to Metarhodopsin II Formation in Visual Transduction

Yin Wang; Ana Vitória Botelho; Gary V. Martinez; Michael F. Brown

doi:10.1021/ja0200488

Electrostatic Properties of Membrane Lipids Coupled to Metarhodopsin II Formation in Visual Transduction

Journal of the American Chemical Society ◽

10.1021/ja0200488 ◽

2002 ◽

Vol 124 (26) ◽

pp. 7690-7701 ◽

Cited By ~ 40

Author(s):

Yin Wang ◽

Ana Vitória Botelho ◽

Gary V. Martinez ◽

Michael F. Brown

Keyword(s):

Membrane Lipids ◽

Visual Transduction ◽

Electrostatic Properties

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The organization of cell surface membrane domains

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155992 ◽

1989 ◽

Vol 47 ◽

pp. 804-805

Author(s):

Michael Edidin

Keyword(s):

Cell Surface ◽

Membrane Lipids ◽

Surface Membrane ◽

Lateral Diffusion ◽

Cell Types ◽

Membrane Domains ◽

Membrane Biology ◽

Morphological Polarity ◽

Discrete Domains ◽

Membrane Components

Cell surface membranes are based on a fluid lipid bilayer and models of the membranes' organization have emphasised the possibilities for lateral motion of membrane lipids and proteins within the bilayer. Two recent trends in cell and membrane biology make us consider ways in which membrane organization works against its inherent fluidity, localizing both lipids and proteins into discrete domains. There is evidence for such domains, even in cells without obvious morphological polarity and organization [Table 1]. Cells that are morphologically polarised, for example epithelial cells, raise the issue of membrane domains in an accute form.The technique of fluorescence photobleaching and recovery, FPR, was developed to measure lateral diffusion of membrane components. It has also proven to be a powerful tool for the analysis of constraints to lateral mobility. FPR resolves several sorts of membrane domains, all on the micrometer scale, in several different cell types.

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Kinetics and energetics of the rhodopsin-transducin-cGMP phosphodiesterase cascade of visual transduction

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/s0005-2728(05)80035-0 ◽

1992 ◽

Vol 1101 (2) ◽

pp. 260-263 ◽

Cited By ~ 2

Author(s):

M CHABRE ◽

T VUONG

Keyword(s):

Visual Transduction ◽

Cgmp Phosphodiesterase

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Melatonin reduces high levels of lipid peroxidation induced by potassium iodate in porcine thyroid

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000628 ◽

2019 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Paulina Iwan ◽

Jan Stepniak ◽

Malgorzata Karbownik-Lewinska

Keyword(s):

Lipid Peroxidation ◽

Oxidative Damage ◽

Membrane Lipids ◽

Chemical Properties ◽

Iodine Concentration ◽

Free Radical Scavenger ◽

Radical Scavenger ◽

Protective Effects ◽

Potassium Iodate ◽

Hormone Synthesis

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.

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