Channelrhodopsin-1 Phosphorylation Changes with Phototactic Behavior and Responds to Physiological Stimuli in Chlamydomonas
| Autor: | Peter Hegemann, Elisabeth Fantisch, Suneel Kateriya, Zarah Kowalzyk, Hanna Erhard, David Boness, Georg Kreimer, Julia Frauenholz, Nadin Marcinkowski, Michaela Böhm |
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| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
0301 basic medicine biology Chlamydomonas Wild type Channelrhodopsin Chlamydomonas reinhardtii Cell Biology Plant Science Optogenetics biology.organism_classification 01 natural sciences 03 medical and health sciences Light intensity 030104 developmental biology Phototaxis Biophysics Phosphorylation 010606 plant biology & botany |
| Zdroj: | The Plant Cell. 31:886-910 |
| ISSN: | 1532-298X |
| DOI: | 10.1105/tpc.18.00936 |
| Popis: | The unicellular alga Chlamydomonas (Chlamydomonas reinhardtii) exhibits oriented movement responses (phototaxis) to light over more than three log units of intensity. Phototaxis thus depends on the cell’s ability to adjust the sensitivity of its photoreceptors to ambient light conditions. In Chlamydomonas, the photoreceptors for phototaxis are the channelrhodopsins (ChR)1 and ChR2; these light-gated cation channels are located in the plasma membrane. Although ChRs are widely used in optogenetic studies, little is known about ChR signaling in algae. We characterized the in vivo phosphorylation of ChR1. Its reversible phosphorylation occurred within seconds as a graded response to changes in the light intensity and ionic composition of the medium and depended on an elevated cytosolic Ca2+ concentration. Changes in the phototactic sign were accompanied by alterations in the phosphorylation status of ChR1. Furthermore, compared with the wild type, a permanently negative phototactic mutant required higher light intensities to evoke ChR1 phosphorylation. C-terminal truncation of ChR1 disturbed its reversible phosphorylation, whereas it was normal in ChR2-knockout and eyespot-assembly mutants. The identification of phosphosites in regions important for ChR1 function points to their potential regulatory role(s). We propose that multiple ChR1 phosphorylation, regulated via a Ca2+-based feedback loop, is an important component in the adaptation of phototactic sensitivity in Chlamydomonas. |
| Databáze: | OpenAIRE |
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