The mobility of phytochrome within protonemal tip cells of the moss Ceratodon purpureus, monitored by fluorescence correlation spectroscopy
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Contributors
Abstract
Fluorescence correlation spectroscopy (FCS) is a versatile tool for investigating the mobilities of fluorescent molecules in cells. In this article, we show that it is possible to distinguish between freely diffusing and membrane-bound forms of biomolecules involved in signal transduction in living cells. Fluorescence correlation spectroscopy was used to measure the mobility of phytochrome, which plays a role in phototropism and polarotropism in protonemal tip cells of the moss Ceratodon purpureus. The phytochrome was loaded with phycoerythrobilin, which is fluorescent only in the phytochrome-bound state. Confocal laser scanning microscopy was used for imaging and selecting the xy measuring position in the apical zone of the tip cell. Fluorescence correlation was measured at ancient z-positions in the cell. Analysis of the diffusion coefficients by nonlinear least-square fits showed a subcellular fraction of phytochrome at the cell periphery with a sixfold higher diffusion coefficient than in the core fraction. This phytochrome is apparently bound to the membrane and probably controls the phototropic and polarotropic response.
Details
Original language | English |
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Pages (from-to) | 2013-2021 |
Number of pages | 9 |
Journal | Biophysical journal |
Volume | 87 |
Issue number | 3 |
Publication status | Published - Sept 2004 |
Peer-reviewed | Yes |
External IDs
PubMed | 15345577 |
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