Journal Article

Protein–protein interactions as a proxy to monitor conformational changes and activation states of the tomato resistance protein I-2

Ewa Lukasik-Shreepaathy, Jack H. Vossen, Wladimir I. L. Tameling, Marianne J. de Vroomen, Ben J. C. Cornelissen and Frank L. W. Takken

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 63, issue 8, pages 3047-3060
Published in print May 2012 | ISSN: 0022-0957
Published online February 2012 | e-ISSN: 1460-2431 | DOI:

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Plant resistance proteins (R) are involved in pathogen recognition and subsequent initiation of defence responses. Their activity is regulated by inter- and intramolecular interactions. In a yeast two-hybrid screen two clones (I2I-1 and I2I-2) specifically interacting with I-2, a Fusarium oxysporum f. sp. lycopersici resistance protein of the CC-NB-LRR family, were identified. Sequence analysis revealed that I2I-1 belongs to the Formin gene family (SlFormin) whereas I2I-2 has homology to translin-associated protein X (SlTrax). SlFormin required only the N-terminal CC I-2 domain for binding, whereas SlTrax required both I-2 CC and part of the NB-ARC domain. Tomato plants stably silenced for these interactors were not compromised in I-2-mediated disease resistance. When extended or mutated forms of I-2 were used as baits, distinct and often opposite, interaction patterns with the two interactors were observed. These interaction patterns correlated with the proposed activation state of I-2 implying that active and inactive R proteins adopt distinct conformations. It is concluded that the yeast two hybrid system can be used as a proxy to monitor these different conformational states.

Keywords: Disease resistance; Fusarium oxysporum; NB-LRR protein; tomato

Journal Article.  9813 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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