Proteomic analysis of the eyespot of Chlamydomonas reinhardtii provides novel insights into its components and tactic movements.
Flagellate green algae have developed a visual system, the eyespot apparatus, which allows the cell to phototax. To further understand the molecular organization of the eyespot apparatus and the phototactic movement that is controlled by light and the circadian clock, a detailed understanding of all components of the eyespot apparatus is needed. We developed a procedure to purify the eyespot apparatus from the green model alga Chlamydomonas reinhardtii. Its proteomic analysis resulted in the identification of 202 different proteins with at least two different peptides (984 in total). These data provide new insights into structural components of the eyespot apparatus, photoreceptors, retina(l)-related proteins, members of putative signaling pathways for phototaxis and chemotaxis, and metabolic pathways within an algal visual system. In addition, we have performed a functional analysis of one of the identified putative components of the phototactic signaling pathway, casein kinase 1 (CK1). CK1 is also present in the flagella and thus is a promising candidate for controlling behavioral responses to light. We demonstrate that silencing CK1 by RNA interference reduces its level in both flagella and eyespot. In addition, we show that silencing of CK1 results in severe disturbances in hatching, flagellum formation, and circadian control of phototaxis.
Schmidt
Melanie
M
Institute of Biology, Friedrich-Alexander-University, D-91058 Erlangen, Germany.
Gessner
Gunther
G
Luff
Matthias
M
Heiland
Ines
I
Wagner
Volker
V
Kaminski
Marc
M
Geimer
Stefan
S
Eitzinger
Nicole
N
Reissenweber
Tobias
T
Voytsekh
Olga
O
Fiedler
Monika
M
Mittag
Maria
M
Kreimer
Georg
G
D020418:Algal Proteins / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000032:analysis; D047389:Casein Kinase I / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D016825:Chlamydomonas reinhardtii / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D002940:Circadian Rhythm; D005407:Flagella / Q000378:metabolism / Q000502:physiology; D008027:Light; D009068:Movement / Q000502:physiology; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis; D010770:Phosphotransferases / Q000032:analysis; D040901:Proteomics; D034622:RNA Interference; D015398:Signal Transduction
D020418:Algal Proteins; D002135:Calcium-Binding Proteins; D010770:Phosphotransferases; D047389:Casein Kinase I; D010744:Phosphoric Monoester Hydrolases; D002118:Calcium