RRC ID 69073
著者 Yamano T, Toyokawa C, Shimamura D, Matsuoka T, Fukuzawa H.
タイトル CO2-dependent migration and relocation of LCIB, a pyrenoid-peripheral protein in Chlamydomonas reinhardtii.
ジャーナル Plant Physiol
Abstract Most microalgae overcome the difficulty of acquiring inorganic carbon (Ci) in aquatic environments by inducing a CO2-concentrating mechanism (CCM). In the green alga Chlamydomonas reinhardtii, two distinct photosynthetic acclimation states have been described under CO2-limiting conditions (low-CO2, LC, and very low-CO2, VLC). LC-inducible protein B (LCIB), structurally characterized as carbonic anhydrase, localizes in the chloroplast stroma under CO2-supplied and LC conditions. In VLC conditions, it migrates to aggregate around the pyrenoid, where the CO2-fixing enzyme Rubisco is enriched. Although the physiological importance of LCIB localization changes in the chloroplast has been shown, factors necessary for the localization changes remain uncertain. Here, we examined the effect of pH, light availability, photosynthetic electron flow, and protein synthesis on the localization changes, along with measuring Ci concentrations. LCIB dispersed or localized in the basal region of the chloroplast stroma at 8.3-15 µM CO2, whereas LCIB migrated toward the pyrenoid at 6.5 µM CO2. Furthermore, LCIB relocated toward the pyrenoid at 2.6-3.4 µM CO2, even in cells in the dark or treated with DCMU and cycloheximide in light. In contrast, in the mutant lacking CCM1, a master regulator of CCM, LCIB remained dispersed even at 4.3 µM CO2. Meanwhile, a simultaneous expression of LCIC, an interacting protein of LCIB, induced the localization of several speckled structures at the pyrenoid periphery. These results suggest that the localization changes of LCIB require LCIC and are controlled by CO2 concentration with ∼7 µM as the boundary.
巻・号 188(2)
ページ 1081-1094
公開日 2022-2-4
DOI 10.1093/plphys/kiab528
PII 6429283
PMID 34791500
PMC PMC8825250
MeSH Carbon Dioxide / metabolism* Carbonic Anhydrases / genetics Carbonic Anhydrases / metabolism* Cell Movement / drug effects* Cell Movement / genetics Chlamydomonas reinhardtii / genetics* Chlamydomonas reinhardtii / metabolism* Chloroplasts / genetics Chloroplasts / metabolism* Gene Expression Regulation, Plant Genes, Plant Plant Proteins / genetics Plant Proteins / metabolism* Plants, Genetically Modified / genetics Plants, Genetically Modified / metabolism
IF 6.902
リソース情報
藻類 NIES-2235