The High Light Response and Redox Control of Thylakoid FtsH Protease in Chlamydomonas reinhardtii.

摘要: In Chlamydomonas reinhardtii, the major protease involved in maintenance of photosynthetic machinery thylakoid membranes, FtsH protease, mostly forms large hetero-oligomers (∼1 MDa) comprising FtsH1 and FtsH2 subunits, whatever light intensity for growth. Upon high exposure, subunits display a shorter half-life, which is counterbalanced by an increase FTSH1/2 mRNA levels, resulting modest upregulation FtsH1/2 proteins. Furthermore, we found that increases activity through hitherto unnoticed redox-controlled reduction intermolecular disulfide bridges. We isolated FTSH1 promoter-deficient mutant, ftsh1-3, from insertion TOC1 transposon, light-induced gene expression largely lost. abundance proteins are loosely coupled (decreased 70% 30%, respectively) with no formation stable homo-oligomers. Using strains exhibiting different accumulation levels subunit after complementation demonstrate tolerance tightly correlated protease. Thus, response to stress involves higher associated into complexes increased proteolytic activity.