Cyclophilin 40 facilitates HSP90-mediated RISC assembly in plants

Iki, Taichiro; Yoshikawa, Manabu; Meshi, Tetsuo; Ishikawa, Masayuki

doi:10.1038/emboj.2011.395

Cited by 146 publications

(133 citation statements)

References 54 publications

(86 reference statements)

Supporting

Mentioning

126

Contrasting

Unclassified

Order By: Relevance

“…The cochaperones of HSP90 are capable of modulating the ATP-hydrolyzing rate of HSP90, recruiting client proteins, or playing chaperone roles on their own (Röhl et al, 2013). Biochemical studies in plants revealed that the cochaperone Cyclophilin 40/SQUINT (CYP40/SQN) in tobacco and Arabidopsis associates with AGO1 in an HSP90-dependent manner and facilitates RISC assembly (Earley and Poethig, 2011;Iki et al, 2012). In line with this, inactivation of SQN impairs miRNA activity in Arabidopsis .…”

Section: Loading Of Small Rnas Into Ago Family Proteinsmentioning

confidence: 96%

RNAi in Plants: An Argonaute-Centered View

2016

View full text Add to dashboard Cite

Argonaute (AGO) family proteins are effectors of RNAi in eukaryotes. AGOs bind small RNAs and use them as guides to silence target genes or transposable elements at the transcriptional or posttranscriptional level. Eukaryotic AGO proteins share common structural and biochemical properties and function through conserved core mechanisms in RNAi pathways, yet plant AGOs have evolved specialized and diversified functions. This Review covers the general features of AGO proteins and highlights recent progress toward our understanding of the mechanisms and functions of plant AGOs.

show abstract

Section: Loading Of Small Rnas Into Ago Family Proteinsmentioning

confidence: 96%

RNAi in Plants: An Argonaute-Centered View

2016

View full text Add to dashboard Cite

show abstract

“…The squint mutation in the Arabidopsis SQN/Cyp40 cyclophilin gene results in a delay of vegetative shoot maturation [95] and a delay of flower meristem termination when combined with other mutations [96]. Similar to TWD1/FKBP42 [65], Arabidopsis SQN/Cyp40 forms a complex with HSP90, facilitating HPS90-mediated protein complex assembly [97].…”

Section: Box 2: Immunophilins In Regulation Of Plant Development and mentioning

confidence: 99%

Master and servant: Regulation of auxin transporters by FKBPs and cyclophilins

2016

View full text Add to dashboard Cite

Plant development and architecture are greatly influenced by the polar distribution of the essential hormone auxin. The directional influx and efflux of auxin from plant cells depends primarily on AUX1/LAX, PIN, and ABCB/PGP/MDR families of auxin transport proteins. The functional analysis of these proteins has progressed rapidly within the last decade thanks to the establishment of heterologous auxin transport systems. Heterologous co-expression allowed also for the testing of protein-protein interactions involved in the regulation of transporters and identified relationships with members of the FK506-Binding Protein (FKBP) and cyclophilin protein families, which are best known in non-plant systems as cellular receptors for the immunosuppressant drugs, FK506 and cyclosporin A, respectively. Current evidence that such interactions affect membrane trafficking, and potentially the activity of auxin transporters is reviewed. We also propose that FKBPs andcyclophilins might integrate the action of auxin transport inhibitors, such as NPA, on members of the ABCB and PIN family, respectively. Finally, we outline open questions that might be useful for further elucidation of the role of immunophilins as regulators (servants) of auxin transporters (masters).

show abstract

“…In plants, Cyps control transcription, gene silencing, and hormone signaling, affecting plant development and interaction with pathogens (Iki et al, 2012;Trupkin et al, 2012;Bannikova et al, 2013). Rotamase Cyp1 (ROC1), one of the best studied Cyps from Arabidopsis (Arabidopsis thaliana), affects plant architecture, hormone and phytochrome signaling, and is a target of the bacterial effector protein AvrRpt2 (Coaker et al, 2005;Trupkin et al, 2012;Ma et al, 2013).…”

mentioning

confidence: 99%

A Redox 2-Cys Mechanism Regulates the Catalytic Activity of Divergent Cyclophilins

et al. 2013

View full text Add to dashboard Cite

The citrus (Citrus sinensis) cyclophilin CsCyp is a target of the Xanthomonas citri transcription activator-like effector PthA, required to elicit cankers on citrus. CsCyp binds the citrus thioredoxin CsTdx and the carboxyl-terminal domain of RNA polymerase II and is a divergent cyclophilin that carries the additional loop KSGKPLH, invariable cysteine (Cys) residues Cys-40 and Cys-168, and the conserved glutamate (Glu) Glu-83. Despite the suggested roles in ATP and metal binding, the functions of these unique structural elements remain unknown. Here, we show that the conserved Cys residues form a disulfide bond that inactivates the enzyme, whereas Glu-83, which belongs to the catalytic loop and is also critical for enzyme activity, is anchored to the divergent loop to maintain the active site open. In addition, we demonstrate that Cys-40 and Cys-168 are required for the interaction with CsTdx and that CsCyp binds the citrus carboxyl-terminal domain of RNA polymerase II YSPSAP repeat. Our data support a model where formation of the Cys-40-Cys-168 disulfide bond induces a conformational change that disrupts the interaction of the divergent and catalytic loops, via Glu-83, causing the active site to close. This suggests a new type of allosteric regulation in divergent cyclophilins, involving disulfide bond formation and a loop-displacement mechanism.

show abstract

Cyclophilin 40 facilitates HSP90-mediated RISC assembly in plants

Cited by 146 publications

References 54 publications

RNAi in Plants: An Argonaute-Centered View

RNAi in Plants: An Argonaute-Centered View

Master and servant: Regulation of auxin transporters by FKBPs and cyclophilins

A Redox 2-Cys Mechanism Regulates the Catalytic Activity of Divergent Cyclophilins

Contact Info

Product

Resources

About