Fluorescence fluctuation analysis of Arabidopsis thaliana somatic embryogenesis receptor-like kinase and brassinosteroid insensitive 1 receptor oligomerization.
Receptor kinases play a key role in the cellular perception of signals. To verify models for receptor activation through dimerization, an experimental system is required to determine the precise oligomerization status of proteins within living cells. Here we show that photon counting histogram analysis and dual-color fluorescence cross correlation spectroscopy are able to monitor fluorescently labeled proteins at the single-molecule detection level in living plant cells. In-frame fusion proteins of the brassinosteroid insensitive 1 (BRI1) receptor and the Arabidopsis thaliana somatic embryogenesis receptor-like kinases 1 and 3 (AtSERK1 and 3) to the enhanced cyan or yellow fluorescent protein were transiently expressed in plant cells. Although no oligomeric structures were detected for AtSERK3, 15% (AtSERK1) to 20% (BRI1) of the labeled proteins in the plasma membrane was found to be present as homodimers, whereas no evidence was found for higher oligomeric complexes.
Hink
Mark A
MA
MicroSpectroscopy Centre, Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands.
Shah
Khalid
K
Russinova
Eugenia
E
de Vries
Sacco C
SC
Visser
Antonie J W G
AJ
D017360:Arabidopsis / Q000737:chemistry / Q000196:embryology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism*; D002478:Cells, Cultured; D019281:Dimerization; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods
D029681:Arabidopsis Proteins; D011494:Protein Kinases; C463660:BAK1 protein, Arabidopsis; C440035:SERK1 protein, Arabidopsis; C108270:BRI1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases