title: PPIase activities and interaction partners of FK506-binding proteins in the wheat thylakoid.
abstract: FK506-binding proteins (FKBPs) and cyclophilins, collectively called immunophilins, conserve peptidyl-prolyl cis/trans isomerase (PPIase) active sites, although many lack PPIase activity. The chloroplast thylakoid contains a large proportion of the plant immunophilin family, but their functions within this compartment are unclear. Some lumenal immunophilins are important for assembly of photosynthetic complexes, implicating them in the maintenance and turnover of the photosynthetic apparatus during acclimation processes. In this investigation into the functions of three FKBPs localized to the thylakoid of Triticum aestivum (wheat), we present the first evidence of PPIase activity in the thylakoid of a cereal plant, and also show that PPIase activity is not conserved in all lumenal FKBPs. Using yeast two-hybrid analysis we found that the PPIase-active FKBP13 interacts with the globular domain of the wheat Rieske protein, with potential impact on photosynthetic electron transfer. Specific interaction partners for PPIase-deficient FKBP16-1 and FKBP16-3 link these isoforms to photosystem assembly.
authors.affiliation: Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122, Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Gollan
authors.forename: Mark
authors.initials: M
authors.lastname: Ziemann
authors.forename: Mrinal
authors.initials: M
authors.lastname: Bhave
mesh_terms: D003001:Cloning, Molecular; D014450:Electron Transport Complex III / Q000378:metabolism; D015723:Gene Library; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism*; D045331:Photosystem I Protein Complex / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D022021:Tacrolimus Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020524:Thylakoids / Q000201:enzymology* / Q000235:genetics; D014908:Triticum / Q000201:enzymology* / Q000235:genetics; D020798:Two-Hybrid System Techniques
chemical_list: D045331:Photosystem I Protein Complex; D010940:Plant Proteins; D018749:RNA, Plant; C037989:Rieske iron-sulfur protein; C070133:FKBP-13; D022021:Tacrolimus Binding Proteins; D019696:Peptidylprolyl Isomerase; D014450:Electron Transport Complex III