Selective Homo- and Heteromer Interactions between the Multiple Organellar RNA Editing Factor (MORF) Proteins in Arabidopsis thaliana*
Selective Homo- and Heteromer Interactions between the Multiple Organellar RNA Editing Factor (MORF) Proteins in Arabidopsis thaliana*
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DOI：
10.1074/jbc.m114.602086
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发表时间：
2015-01
期刊：
影响因子：
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通讯作者：
A. Zehrmann;Barbara Härtel;F. Glass;Eszter Bayer-Császár;Toshihiro Obata;E. Meyer;A. Brennicke;M. T
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文献类型：
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作者：
A. Zehrmann;Barbara Härtel;F. Glass;Eszter Bayer-Császár;Toshihiro Obata;E. Meyer;A. Brennicke;M. T
Background: RNA editing in plant organelles requires at least one of nine MORF proteins. Results: MORF proteins connect in specific homo- and heteromeric protein-protein interactions. Conclusion: The observed homo- and heteromeric combinations of MORF proteins explain why full editing can require two MORFs but one MORF can sustain basal editing levels. Significance: These findings will help to better understand RNA editing in plant organelles. RNA editing in plastids and mitochondria of flowering plants requires pentatricopeptide repeat proteins (PPR proteins) for site recognition and proteins of the multiple organellar RNA editing factor (MORF) family as cofactors. Two MORF proteins, MORF5 and MORF8, are dual-targeted to plastids and mitochondria; two are targeted to plastids, and five are targeted to mitochondria. Pulldown assays from Arabidopsis thaliana tissue culture extracts with the mitochondrial MORF1 and the plastid MORF2 proteins, respectively, both identify the dual-targeted MORF8 protein, showing that these complexes can assemble in the organelles. We have now determined the scope of potential interactions between the various MORF proteins by yeast two-hybrid, in vitro pulldown, and bimolecular fluorescence complementation assays. The resulting MORF-MORF interactome identifies specific heteromeric MORF protein interactions in plastids and in mitochondria. Heteromers are observed for MORF protein combinations affecting a common site, suggesting their functional relevance. Most MORF proteins also undergo homomeric interactions. Submolecular analysis of the MORF1 protein reveals that the MORF-MORF protein connections require the C-terminal region of the central conserved MORF box. This domain has no similarity to known protein modules and may form a novel surface for protein-protein interactions.
