Chloroplast protease/chaperone AtDeg2 holds γ1 subunit of ATP synthase in an unaggregated state under high irradiance conditions in Arabidopsis thaliana

• Published in: Photosynthetica Vol. 60; no. 2; pp. 212 - 218
• Main Authors: JAGODZIK, P., JACKOWSKI, G.
• Format: Journal Article
• Language: English
• Published: Academy of Sciences of the Czech Republic, Institute of Experimental Botany 02.05.2022
• Subjects: chaperone; deg2; elevated irradiance; homodimerization; protease
• ISSN: 0300-3604; 1573-9058
• DOI: 10.32615/ps.2022.004

Little data on the role played in vivo by chloroplast protein AtDeg2 as a chaperone is available. Therefore, we sought for chloroplast proteins protected from high irradiance-induced interprotein aggregation via disulphide bridges by AtDeg2 acting as a holdase. To reach this goal, we performed analyses which involved comparative diagonal electrophoreses of lysates of chloroplasts isolated from wild type (WT) plants and transgenic plants 35S:AtDEG2ΔPDZ1-GFP which expressed AtDeg2 lacking its chaperone activity but retaining the protease activity. The results of the analyses indicate that AtDeg2 acting as a holdase prevents a single chloroplast protein, i.e., the γ1 subunit of ATP synthase from long-term high irradiance-induced homodimerization mediated by disuplhide bridges and this allows us to better understand a complexity of physiological significance of AtDeg2 - the chloroplast protein of dual protease/chaperone activity.