Preparation of Chloroplast Lipid Membrane and Lipid-protein Interaction Assay

Measurements of lateral molecular diffusion on blebs formed on the surfaces of isolated muscle cells and myoblasts are reported. These blebbed membranes retain integral proteins but apparently separate from the detectable cytoskeleton. On blebs, acetylcholine receptors, concanavalin A receptors, and stearoyldextran extrinsic model receptor molecules are free to diffuse with a diffusion coefficient (D) approximately 3 x 10(-9) cm2/s, which is close to the value predicted for hydrodynamic drag in the lipid membrane. In contrast, diffusion of these typical receptors in intact cell membranes is constrained to D approximately less than 10(-10) cm2/s with substantial fractions virtually nondiffusible (D less than 10(-12) cm2/s). Lipid analog diffusion is also slightly enhanced in blebs as expected of evanescent lipid protein interaction. This strong enhancement of membrane protein diffusion is attributed to release from unidentified natural constraints that is induced in some way by detachment of the bleb membrane.

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The membrane lateral domain approach in the studies of lipid–protein interaction of GPI-anchored bovine erythrocyte acetylcholinesterase

European Biophysics Journal ◽

10.1007/s00249-004-0417-0 ◽

2004 ◽

Vol 33 (8) ◽

pp. 715-725 ◽

Cited By ~ 15

Author(s):

Zoran Arsov ◽

Milan Schara ◽

Matjaž Zorko ◽

Janez Štrancar

Keyword(s):

Protein Interaction ◽

Bovine Erythrocyte ◽

Lipid Protein Interaction

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Arachidonic acid and its metabolites increase Cai in cultured rat oligodendrocytes

AJP Cell Physiology ◽

10.1152/ajpcell.1993.264.3.c632 ◽

1993 ◽

Vol 264 (3) ◽

pp. C632-C640 ◽

Cited By ~ 28

Author(s):

B. Soliven ◽

M. Takeda ◽

T. Shandy ◽

D. J. Nelson

Keyword(s):

Spinal Cord ◽

Arachidonic Acid ◽

Linoleic Acid ◽

Intracellular Calcium ◽

Protein Interaction ◽

Membrane Lipid ◽

Rat Spinal Cord ◽

Fura 2 ◽

Fluorescence Measurements ◽

Lipid Protein Interaction

Fluorescence measurements of intracellular calcium (Cai) were made on cultured rat spinal cord oligodendrocytes (OLGs) using the dye fura-2. Exposure of OLGs to arachidonic acid (AA) (5-50 microM) elicited a concentration-dependent increase in Cai that was derived mainly from extracellular Ca2+. AA at 50 microM also released Ca2+ from intracellular stores. The response to AA was not decreased by nifedipine or by inhibition of Na(+)-Ca2+ exchange. AA-induced Ca2+ influx pathway was permeable to Mn2+ and Co2+ but not to Ba2+ and was not markedly influenced by depolarization, suggesting that AA activates a voltage-independent, not strictly selective, Ca2+ channel. The Cai response to AA was partially attenuated in the presence of indomethacin, indicating that the Cai response was mediated in part by cyclooxygenase products of AA. However, the AA-induced Cai response far exceeded that induced by prostaglandins and was mimicked by linoleic acid. We conclude that AA modulates Cai of OLGs via two mechanisms: 1) indirectly via cyclooxygenase pathway and 2) directly via membrane lipid-protein interaction.

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