Abstract

Plants regulate cell division and cell expansion through the action of the phytohormone auxin.Auxin is a vital small molecule whose effects on growth and development are conveyed throughthe interactions and regulation of three protein families: TRANSPORT INHIBITORRESPONSE1/AUXIN BINDING F-BOX1-5 (TIR1/AFB), AUXIN RESPONSE FACTOR(ARF) transcription factors, and AUXIN/INDOLE 3-ACETIC ACID INDUCIBLE (Aux/IAA)repressor proteins. Whereas the stability of and protein-protein interactions between theTIR1/AFB and Aux/IAA protein families have been well studied, the interactions within theARF protein family and between the ARF and Aux/IAA protein families is less understood. Here, we describe the studies we undertook to determine the structure of an ARF interaction domain. We further characterize this domain using complementary biochemical, biophysical, and in planta approaches. We highlight the importance of conserved structural motifs within the domain that are necessary for auxin signaling and established a new binding model. Finally, we use a combination of forward genetics and cell biology approaches to identify a novel protein required for regulating the stability of ARF proteins. Taken together, this work highlights new insights into the importance of ARF•ARF and ARF•Aux/IAA protein-protein interactions, as well as a new understanding of both ARF protein stability and cellular localization.

Committee Chair

Lucia C Strader

Committee Members

Gaya Amarasinghe, Barbara Kunkel, Sona Pandey, Hani Zaher,

Comments

Permanent URL: https://doi.org/10.7936/K7BC3WRW

Degree

Doctor of Philosophy (PhD)

Author's Department

Biology & Biomedical Sciences (Plant & Microbial Biosciences)

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

Summer 8-15-2015

Language

English (en)

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Available for download on Thursday, August 15, 2115

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Biology Commons

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