| 1. |
- Jacobson, Ken, et al.
(författare)
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Lipid flow in locomoting cells : Response
- 1991
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 251:4991, s. 318-318
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Tidskriftsartikel (refereegranskat)abstract
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| 2. |
- Lee, Juliet, et al.
(författare)
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The direction of membrane lipid flow in locomoting polymorphonuclear leukocytes
- 1990
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Ingår i: Science. - : American Association for the Advancement of Science. - 0036-8075 .- 1095-9203. ; 247:4947, s. 1229-1233
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to determine the direction of membrane lipid flow in locomoting cells. The plasma membrane of human polymorphonuclear leukocytes was stained with a fluorescent lipid analog dihexadecanoyl indocarbocyanine. A line was photobleached on the cell surface perpendicular to the direction of cell motion. Low-light-level fluorescence microscopy and digital image-processing techniques were used to analyze a series of images taken at short intervals after photobleaching. The bleached line remained visible for about 5 seconds before being erased by diffusional recovery. Examination of fluorescence intensity profiles allowed a comparison to be made between the velocities of line and cell movement. Results indicate that the bleached line moves forward with the same velocity as the cell during locomotion, refuting the retrograde lipid flow model of locomotion. Instead, the plasma membrane lipid appears to move forward according to either the unit movement of membrane or the tank track model of locomotion.
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| 3. |
- Stendahl, Olle, et al.
(författare)
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Redistribution of intracellular Ca2+ stores during phagocytosis in human neutrophils
- 1994
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 265:5177, s. 1439-1441
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Tidskriftsartikel (refereegranskat)abstract
- Subcellular gradients of cytosolic free Ca2+ concentration, [Ca2+]i, are thought to be critical for the localization of functional responses within a cell. A potential but previously unexplored mechanism for the generation of gradients of [Ca2+]i is the accumulation of Ca2+ stores at the site of Ca2+ action. The distribution of the Ca2+ store markers Ca(2+)-dependent adenosine triphosphatase and calreticulin was investigated in resting and phagocytosing human neutrophils. Both proteins showed an evenly distributed fine granular pattern in nonphagocytosing cells, but became markedly concentrated in the filamentous actin-rich cytoplasmic area around the ingested particle during phagocytosis. This redistribution began at early stages of phagocytosis and did not depend on an increase in [Ca2+]i. Thus, accumulation of Ca2+ stores in a restricted area of the cell may contribute to the generation of localized increases in [Ca2+]i.
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