TY - JOUR

T1 - Structures and short linear motif of disordered transcription factor regions provide clues to the interactome of the cellular hub radical-induced cell death1

AU - O'Shea, Charlotte

AU - Staby, Lasse

AU - Bendsen, Sidsel Krogh

AU - Tidemand, Frederik Grønbæk

AU - Redsted, Andreas

AU - Willemoës, Martin

AU - Kragelund, Birthe Brandt

AU - Skriver, Karen

N1 - Copyright © 2016, The American Society for Biochemistry and Molecular Biology.

PY - 2017/1/13

Y1 - 2017/1/13

N2 - Intrinsically disordered protein regions (IDRs) lack a well-defined three-dimensional structure, but often facilitate key protein functions. Some interactions between IDRs and folded protein domains rely on short linear motifs (SLiMs). These motifs are challenging to identify, but once found can point to larger networks of interactions, such as with proteins that serve as hubs for essential cellular functions. The stress-associated plant protein Radical-Induced Cell Death1 (RCD1) is one such hub, interacting with many transcription factors via their flexible IDRs. To identify the SLiM bound by RCD1, we analyzed the IDRs in three protein partners - DREB2A, ANAC013, and ANAC046 - considering parameters such as disorder, context, charges, and pI. Using a combined bioinformatics and experimental approach, we have identified the bipartite RCD1-binding SLiM as [DE]-x(1,2)-[YF]-x(1,4)-[DE]-L, with essential contributions from conserved aromatic, acidic, and leucine residues. Detailed thermodynamic analysis revealed both favorable and unfavorable contributions from the IDRs surrounding the SLiM to the interactions with RCD1, and the SLiM affinities ranged from low nanomolar to 50 times higher Kd's. Specifically, although the SLiM was surrounded by IDRs, individual intrinsic α-helix propensities varied as shown by CD spectroscopy. NMR spectroscopy further demonstrated that DREB2A underwent coupled folding and binding with α-helix formation upon interaction with RCD1, while peptides from ANAC013 and ANAC046 formed different structures or were fuzzy in the complexes. These findings allow us to present a model of the stress-associated RCD1-transcription factor interactome and to contribute to the emerging understanding of the interactions between folded hubs and their intrinsically disordered partners.

AB - Intrinsically disordered protein regions (IDRs) lack a well-defined three-dimensional structure, but often facilitate key protein functions. Some interactions between IDRs and folded protein domains rely on short linear motifs (SLiMs). These motifs are challenging to identify, but once found can point to larger networks of interactions, such as with proteins that serve as hubs for essential cellular functions. The stress-associated plant protein Radical-Induced Cell Death1 (RCD1) is one such hub, interacting with many transcription factors via their flexible IDRs. To identify the SLiM bound by RCD1, we analyzed the IDRs in three protein partners - DREB2A, ANAC013, and ANAC046 - considering parameters such as disorder, context, charges, and pI. Using a combined bioinformatics and experimental approach, we have identified the bipartite RCD1-binding SLiM as [DE]-x(1,2)-[YF]-x(1,4)-[DE]-L, with essential contributions from conserved aromatic, acidic, and leucine residues. Detailed thermodynamic analysis revealed both favorable and unfavorable contributions from the IDRs surrounding the SLiM to the interactions with RCD1, and the SLiM affinities ranged from low nanomolar to 50 times higher Kd's. Specifically, although the SLiM was surrounded by IDRs, individual intrinsic α-helix propensities varied as shown by CD spectroscopy. NMR spectroscopy further demonstrated that DREB2A underwent coupled folding and binding with α-helix formation upon interaction with RCD1, while peptides from ANAC013 and ANAC046 formed different structures or were fuzzy in the complexes. These findings allow us to present a model of the stress-associated RCD1-transcription factor interactome and to contribute to the emerging understanding of the interactions between folded hubs and their intrinsically disordered partners.

U2 - 10.1074/jbc.M116.753426

DO - 10.1074/jbc.M116.753426

M3 - Journal article

C2 - 27881680

VL - 292

SP - 512

EP - 527

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 2

ER -