Ultrabithorax, an intrinsically disordered protein, use topology to select protein interactions

Wednesday, October 10, 2012 — Poster Session II
Noon – 2:00 p.m	Natcher Conference Center, Building 45	OD	MOLBIO-5

Authors

• H.C. Hsiao
• D.J. Cantanese
• K. Gonzalez
• K.S. Matthews
• S.E. Bondos

Abstract

In the classical protein structure-function paradigm, protein function is determined by the protein’s three dimensional structure. In particular, protein-protein interaction would be largely defined by complementary surface topologies. However, proteins that engage in multiple interactions, including cellular signaling proteins and transcription factors, are likely to include intrinsically disordered regions. Topological flexibility gives these proteins the ability to irreversibly, yet specifically interact with many other proteins. Given their lack of structure, how do intrinsically disordered proteins select the contact binding partners? We are answering this question using Hox protein as a model system. The Hox protein family acts near the top of developmental transcription regulatory hierarchy in all bilaterally symmetric animals. Hox protein function requires extensive protein interactions with diverse cell signaling protein and transcription factors. We are testing the selectivity of the Drosophila Hox protein-Ultrabithorax (Ubx), an experimentally proven intrinsically disordered protein using yeast two hybrid assay. Despite the ability of Ubx to bind a wide array of proteins, our results shockingly indicate that Ubx selects partners by topology. Intriguingly, these proteins bind the intrinsically disordered regions within Ubx. This result suggests that both structured and intrinsically disordered protein interaction use similar criteria to select binding partners.

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