AtFtsH heterocomplex-mediated degradation of apoproteins of the major light harvesting complex of photosystem II (LHCII) in response to stresses

摘要: Chloroplastic heterocomplex consisting of AtFtsH1, 2, 5 and 8 proteases, integrally bound to thylakoid membrane was shown play a critical role in degradation photodamaged PsbA molecules, inherent photosystem II (PSII) repair cycle plastid development. As no one apoproteins besides has been identified as target for the heterocomplex-mediated we investigated significance this protease complex major light harvesting (LHCII) response various stressing conditions stress-related changes overall composition LHCII trimers PSII-enriched membranes (BBY particles). To reach goal combination approaches applied based on immunoblotting, vitro non-denaturing isoelectrofocusing. Exposure Arabidopsis thaliana leaves desiccation, cold high irradiance led step-wise disappearance Lhcb1 Lhcb2, while Lhcb3 level remained unchanged, except which caused significant decrease. Furthermore, it demonstrated that stress-dependent Lhcb1–3 is proteolytic phenomenon metalloprotease responsible. No were observed due exposition var1-1 mutant three stresses clearly pointing involvement AtFtsH irradiance-dependent Lhcb2 Lhcb3. Non-denaturing isoelectrofocusing analyses revealed heterocomplex-dependent differential behaviour following desiccation stress accompanied by modulations abundances individual BBY particles resisted modulations.