Defining a Two-pronged Structural Model for PB1 (Phox/Bem1p) Domain Interaction in Plant Auxin Responses
- Washington Univ., St. Louis, MO (United States)
- Washington Univ. School of Medicine, St. Louis, MO (United States)
- Univ. of Wisconsin, Madison, WI (United States)
- Iowa State Univ., Ames, IA (United States)
Phox/Bem1p (PB1) domains are universal structural modules that use surfaces of different charge for protein-protein association. In plants, PB1-mediated interactions of auxin response factors (ARF) and auxin/indole 3-acetic acid inducible proteins regulate transcriptional events modulated by the phytohormone auxin. Here we investigate the thermodynamic and structural basis for Arabidopsis thaliana ARF7 PB1 domain self-interaction. Isothermal titration calorimetry and NMR experiments indicate that key residues on both the basic and acidic faces of the PB1 domain contribute to and organize coordinately to stabilize protein-protein interactions. Calorimetric analysis of ARF7PB1 site-directed mutants defines a two-pronged electrostatic interaction. Furthermore, the canonical PB1 interaction between a lysine and a cluster of acidic residues provides one prong with an arginine and a second cluster of acidic residues defining the other prong. Evolutionary conservation of this core recognition feature and other co-varying interface sequences allows for versatile PB1-mediated interactions in auxin signaling.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- National Institutes of Health (NIH); National Science Foundation (NSF); USDA, National Institute of Food and Agriculture (NIFA)
- Grant/Contract Number:
- P41GM103399; P41RR002301; S10RR02781; S10RR08438; S10RR023438; S10RR025062; S10RR029220; DMB-8415048; OIA-9977486; BIR-9214394; R00 GM089987-03; MOW-2010-05240; MOW-2014-01877; MCB-1157771
- OSTI ID:
- 1351393
- Journal Information:
- Journal of Biological Chemistry, Vol. 290, Issue 20; ISSN 0021-9258
- Publisher:
- American Society for Biochemistry and Molecular BiologyCopyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
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