Project Details
Projekt
Proteomic analysis of the eyespot of Chlamydomonas reinhardtii and functional characterization of components involved in tactic movements
Applicant
Professor Georg Kreimer
Subject Area
Plant Biochemistry and Biophysics
Term
from 2007 to 2010
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 5470163
The model green alga Chlamydomonas reinhardtii exhibits photo- and chemotactic movements. Both signaling pathways converge possibly at the level of membrane depolarization and Ca2+ is intricately involved in both responses at different levels. We have developed a procedure to purify the primitive visual system for phototaxis, the eyespot, of this alga. In the following proteomic approach, 202 proteins of the eyespot fraction were identified with at least two different peptides (984 in total). The identified proteins include e.g. structural components, photoreceptors, as well as members of metabolic and putative signaling pathways for tactic movements. Now our aim is to get functional information about two selected proteins from this proteome: (i) a Ca2+ sensing receptor and (ii) a protein related to a cyanobacterial chemotaxis receptor. Among the identified proteins were also kinases and phosphatases, indicating that phosphorylation/ dephosphorylation is important for signaling related to the eyespot. Silencing of one of the kinases, casein kinase 1(CK1), affects the circadian control of phototaxis. However, nothing is yet known about the targets of kinases in the eyespot. Therefore we will also analyze the eyespot phosphoproteome and do comparative quantitative phosphoproteomics with eyespots isolated from CK1-silenced and wild-type cells to identify potential targets of CK1 and other kinases in this primitive visual system. Thereby we hope to contribute to the further understanding of signaling pathways involved in tactic movements of C. reinhardtii.
DFG Programme
Research Units
