Plant immunophilins: a review of their structure-function relationship

• Published in: Biochimica et biophysica acta Vol. 1850; no. 10; pp. 2145 - 2158
• Main Authors: Vasudevan, Dileep, Gopalan, Gayathri, Kumar, Ashish, Garcia, Veder J., Luan, Sheng, Swaminathan, Kunchithapadam
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2015; Elsevier
• Subjects: animals; bacteria; binding proteins; catalysts; Cyclophilin; cyclophilins; Cyclophilins - chemistry; Cyclophilins - genetics; Cyclophilins - metabolism; Cyclosporin; drugs; FK506; FKBP; functional diversity; functional properties; fungi; Immunophilin; immunosuppression; molecular chaperones; photosynthesis; plant biology; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; plants (botany); Plants - enzymology; Plants - genetics; protein folding; Protein Structure, Tertiary; receptors; Redox; sequence homology; Structure-Activity Relationship; structure-activity relationships; Tacrolimus Binding Proteins - chemistry; Tacrolimus Binding Proteins - genetics; Tacrolimus Binding Proteins - metabolism; thylakoids; viruses; Redox; FKBP; Cyclosporin; FK506; Cyclophilin; Immunophilin
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2014.12.017

Originally discovered as receptors for immunosuppressive drugs, immunophilins consist of two major groups, FK506 binding proteins (FKBPs) and cyclosporin A binding proteins (cyclophilins, CYPs). Many members in both FKBP and CYP families are peptidyl prolyl isomerases that are involved in protein folding processes, though they share little sequence homology. It is not surprising to find immunophilins in all organisms examined so far, including viruses, bacteria, fungi, plants and animals, as protein folding represents a common process in all living systems. Studies on plant immunophilins have revealed new functions beyond protein folding and new structural properties beyond that of typical PPIases. This review focuses on the structural and functional diversity of plant FKBPs and CYPs. The differences in sequence, structure as well as subcellular localization, have added on to the diversity of this family of molecular chaperones. In particular, the large number of immunophilins present in the thylakoid lumen of the photosynthetic organelle, promises to deliver insights into the regulation of photosynthesis, a unique feature of plant systems. However, very little structural information and functional data are available for plant immunophilins. Studies on the structure and function of plant immunophilins are important in understanding their role in plant biology. By reviewing the structural and functional properties of some immunophilins that represent the emerging area of research in plant biology, we hope to increase the interest of researchers in pursuing further research in this area. This article is part of a Special Issue entitled Proline-directed Foldases: Cell Signaling Catalysts and Drug Targets. •We review the structural and functional diversity of plant FKBPs and CYPs.•Plants have the largest diversity with respect to immunophilins; both FKBPs and CYPs.•Plant immunophilins perform functions beyond protein folding.•They function in protein assembly, hormone signaling, stress-response and immunity.•They reveal structural features not seen in immunophilins from other organisms.