Graduate Thesis Or Dissertation
 

Assembly and Regulation of WW-PPXY Complexes in Hippo Signaling

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/dz010x76d

Descriptions

Attribute NameValues
Creator
Abstract
  • The Hippo signaling pathway is an evolutionarily conserved regulator of cell growth, proliferation, and apoptosis. A key function of the pathway is to regulate the subcellular distribution and activity of Yorkie in Drosophila or Yes-associated protein (YAP) and transcription co-activator with PDZ-binding motif (TAZ) in mammals. The dysregulation of the Hippo signaling pathway has been linked to a variety of diseases, including cancer, making it a highly valuable target for therapeutic development. A unique property of the pathway is the prevalence of proteins containing WW domains, small globular domains that mediate protein-protein interactions through recognition of PPXY motifs. Many of these proteins are multivalent, containing multiple WW domains or PPXY motifs, but the function of this multivalency in complex formation is not well understood. Additionally, several of these WW domain-containing proteins interact with the same PPXY motif-containing proteins and vice versa, and it is not well understood how partner selectivity is accomplished. Understanding the contribution of multivalency to complex assembly and how partner selectivity is achieved may help guide the development of drugs or therapeutics to treat diseases such as cancer. This thesis reports on work focused on analyzing the interactions of a multivalent Drosophila PPXY motif-containing protein to a WW domain binding partner, as well as the mammalian orthologs of these proteins. Chapter 1 provides an introduction to the Hippo signaling pathway, WW domains, and the role of WW domain-PPXY motif interactions in the pathway. Chapter 2 presents studies on the solution properties of the PPXY motif-containing region of Warts, a serine/threonine kinase that regulates Yorkie activity, and its interactions with the tandem WW domains of Yorkie. We show that this region of Warts, which contains five PPXY motifs, is monomeric and primarily disordered, except for some helicity present in the C-terminal region of the protein. We also demonstrate that Warts and Yorkie form an ensemble of interconverting complexes of varying Yorkie stoichiometries, with Yorkie binding to specific PPXY motif combinations with varying stabilities. Chapter 3 is an investigation into the molecular features that contribute to complex stability in Yorkie-Warts interactions. We show that physical features of the linkers connecting PPXY sites contribute to complex stability. Short or structured linkers result in stronger binding, while both positively and negatively charged residues near the PPXY motifs weaken binding. Chapter 4 investigates the mammalian orthologs of Yorkie and Warts, YAP and LATS1 respectively, and an additional WW domain containing protein, KIBRA. We demonstrate that KIBRA and YAP bind to specific motifs on LATS1 to form a ternary complex. Finally, chapter 5 discusses the impacts and highlights of the reported work and outlines future projects. These results expand our understanding of how these proteins interact with another. In particular, this work provides novel insight into how multivalency contributes to complex assembly in these interactions and emphasizes the need to use multivalent constructs to capture all of the contributors to binding affinity.
License
Resource Type
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Rights Statement
Funding Statement (additional comments about funding)
  • Work supported by National Science Foundation grant number 2114544.
  • Work supported by a New Investigator Award from the Medical Research Foundation of Oregon.
Publisher
Peer Reviewed
Language
Embargo reason
  • Pending Publication
Embargo date range
  • 2021-12-10 to 2023-01-10

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details BakerKasieJ2021.pdf 2021-12-09 Public Download