PSA3, a Protein on the Stromal Face of the Thylakoid Membrane, Promotes Photosystem I Accumulation in Cooperation with the Assembly Factor PYG7.

نویسندگان

  • Jie Shen
  • Rosalind Williams-Carrier
  • Alice Barkan
چکیده

PSI is a large protein-pigment complex located in the thylakoid membrane in cyanobacteria, plants, and algae. Although the structure and components of PSI are well characterized, mechanisms that orchestrate its assembly are poorly understood. In this study, we discovered a novel nucleus-encoded protein, Photosystem I Assembly3 (PSA3), that is required for PSI accumulation. PSA3 is conserved among green photosynthetic eukaryotes but is lacking in cyanobacteria. Mutations in the psa3 gene cause the specific loss of PSI in Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). Ribosome profiling and pulse-labeling analyses showed that chloroplast- encoded PSI subunits are synthesized at normal rates in psa3 mutants, indicating that PSA3 is involved in the biogenesis of PSI at a posttranslational step. PSA3 resides on the stromal face of the thylakoid membrane, where it is found in a complex that is slightly smaller than PSI. Structural predictions suggest that PSA3 binds a basic peptide in a manner that is sensitive to the oxidation state of Cys pairs flanking the predicted peptide binding groove. PSA3 and the previously described PSI biogenesis factor PYG7 interact in yeast two-hybrid and bimolecular fluorescence complementation assays, and they are found in thylakoid membrane complexes of similar size. These and other results indicate that PSA3 cooperates with PYG7 to promote the stable assembly of PSI, and that the PsaC subunit is likely to be the primary target of their action.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

PSA3, a Protein on the Stromal Face of the Thylakoid Membrane, Promotes Photosystem I Accumulation in Cooperation with the Assembly Factor PYG71[OPEN]

PSI is a large protein-pigment complex located in the thylakoid membrane in cyanobacteria, plants, and algae. Although the structure and components of PSI are well characterized, mechanisms that orchestrate its assembly are poorly understood. In this study, we discovered a novel nucleus-encoded protein, Photosystem I Assembly3 (PSA3), that is required for PSI accumulation. PSA3 is conserved amo...

متن کامل

MET1 is a thylakoid-associated TPR protein involved in photosystem II supercomplex formation and repair in Arabidopsis.

Photosystem II (PSII) requires constant disassembly and reassembly to accommodate replacement of the D1 protein. Here, we characterize Arabidopsis thaliana MET1, a PSII assembly factor with PDZ and TPR domains. The maize (Zea mays) MET1 homolog is enriched in mesophyll chloroplasts compared with bundle sheath chloroplasts, and MET1 mRNA and protein levels increase during leaf development concom...

متن کامل

Cooperation of LPA3 and LPA2 is essential for photosystem II assembly in Arabidopsis.

Photosystem II (PSII) is a multisubunit membrane protein complex that is assembled in a sequence of steps. However, the molecular mechanisms responsible for the assembly of the individual subunits into functional PSII complexes are still largely unknown. Here, we report the identification of a chloroplast protein, Low PSII Accumulation3 (LPA3), which is required for the assembly of the CP43 sub...

متن کامل

TerC – an essential protein for the integration of CP43 into the thylakoid membrane and its assembly into photosystem II

I Summary During evolution, most genes of the cyanobacterial ancestor of plastids were transferred to the nuclear genome of the host cell (endosymbiosis). Consequently, to maintain the physiological properties of plastids, new regulatory elements and protein import machineries have evolved. For proper assembly of the photosystem II complex, whose core proteins are still plastid encoded, several...

متن کامل

Crystallization of the light-harvesting chlorophyll a/b complex within thylakoid membranes

We have found that treatment of the photosynthetic membranes of green plants, or thylakoids, with the nonionic detergent Triton X-114 at a 10:1 ratio has three effects: (a) photosystem I and coupling factor are solubilized, so that the membranes retain only photosystem II (PS II) and its associated light-harvesting apparatus (LHC-II); (b) LHC-II is crystallized, and so is removed from its norma...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Plant physiology

دوره 174 3  شماره 

صفحات  -

تاریخ انتشار 2017