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The Mobility of Phytochrome within Protonemal Tip Cells of the Moss Ceratodon purpureus, Monitored by Fluorescence Correlation Spectroscopy

Authors :
Guido Böse
Tilman Lamparter
Petra Schwille
Source :
Biophysical Journal
Publication Year :
2004
Publisher :
Elsevier BV, 2004.

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

ISSN :
00063495
Volume :
87
Database :
OpenAIRE
Journal :
Biophysical Journal
Accession number :
edsair.doi.dedup.....44167a456eb7741e06a95e8679f0f5b5
Full Text :
https://doi.org/10.1529/biophysj.103.038521