This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Böse, G. Articles by Lamparter, T. Search for Related Content PubMed PubMed Citation Articles by Böse, G. Articles by Lamparter, T.

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

Guido Böse ^*, Petra Schwille ^*  and Tilman Lamparter 

^* Max-Planck-Institute for Biophysical Chemistry, Göttingen, D-37077 Germany; Center of Biotechnology, Dresden University of Technology, c/o Max-Planck-Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany; and Freie Universität, Pflanzenphysiologie, D-14195 Berlin, Germany

Correspondence: Address reprint requests to Petra Schwille, TU Dresden, MPI for Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, 01307 Dresden, Germany. Tel.: 49-351-210-1444; E-mail: pschwil{at}gwdg.de or Tilman Lamparter, Freie Universität Berlin, Pflanzenphysiologie, Königin Luise Str. 12-16, D-14195 Berlin, Germany. Tel.: 49-0-30-838-54918; Fax: 49-0-30-838-54357; E-mail: lamparte{at}zedat.fu-berlin.de.

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.