Poster: Temperature Responses

Abs # 174: Plant co chaperones FKBPs are involved in development

Presenter:	Breiman, Adina , adina@post.tau.ac.il
Authors	Breiman, Adina  (A)   Bocovza, Shmuel  (A)   Wilunsky, Ruth  (A)
Affiliations:	(A): Dept of Plant Sciences,Tel Aviv University, Israel ,69978

The FKBPs(FK506) binding proteins belong to a large fomily of conserved proteins.The FKBPs possess a domain of peptidyl prolyl cis trans isomerase (PPIase)which affects the folding of their protein substrates.The large FKBPs possess in addition to the PPIase domain 2 additional FKBP like domains with apparently no enzymatic activity and also a TPR domain which interacts with HSP90 and the calmodulin binding domain. The large plant FKBPs show 50% sequence identity to their mammalian counterparts,and can exchange them functionally by binding to hsp90, to dynein and provide an active steroid receptor in cell free systems.We have studied the large FKBPs in wheat and recently in Arabidopsis.Transgenic rice and Arabidopsis plants overproducing the full and truncated FKBPs missing the TPR and calmodulin domains revealed the importance of these domains to protein function. Plants missing these domains were male sterile and their meristems were fasciated. The Arabidopsis FKBPs rof1 and rof2 are heat shock proteins and possess 3 FKBP12 like domains , a TPR domain and a calmodulin binding domain.To further understand the role of the FKBPs in plants, we have started to analyse the Arabidopsis knockout mutants rof1 and rof2 and the overexpressors of the full and truncated wheat FKBPs.The phenotypic and molecular characterisation of these plants will reveal their involvement in plant development. Their expression in flowers and their interaction with hsp90 which was recently shown to be a phenotypic capacitor indicate that the plant FKBPs function are not only chaperones but play an important role in stress response and development.