Non-specific lipid transfer proteins (ns-LTPs) belong to a large family of plant proteins whose function in vivo remains unknown. On the basis of their structure, properties and functions two main classes of lipid transfer protein have been identified in plants, ns-LTP1 and ns-LTP2 respectively. The most interesting structural feature of the ns-LTP proteins is the presence of four amphipatic α-helices which form the internal hydrophobic cavity that can bind the lipid molecules.

Primary defined as the cellular receptors for immunosuppressive drugs, the immunophilins encompass two ubiquitous protein families. They consist of the FK506 binding proteins termed as FKBPs and cyclosporin binding proteins referred to as cyclophilins. They have been found in all orga- nisms. The 52 genes encode immunophilins have been identified in A. thaliana genome, among which 23 encode putative FKBP and 29 putative cyclophilins. Despite the various structure both families have peptidyl-prolyl cis/trans isomerase (PPIase) activity.