The Identification and Characterization of Sufu Interacting Proteins

Open Access
Valerio, Emily Anne
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Aimin Liu, Thesis Supervisor
  • Gong Chen, Honors Advisor
  • Hh signaling
  • Sufu
  • Gli
  • T131L
  • LOC67513
  • Gps1
The Hedgehog (Hh) pathway, activated by a special family of proteins, is a prominent pathway in mammalian development and also in the formation of various cancers. When interacting with cells, Hh ligands are responsible for enhancing target Hh gene expression through the activation of Gli-transcriptional activators. Suppressor of Fused (Sufu) is a specific Gli-interacting protein that functions in negatively regulating Gli activity and by doing so, suppressing Gli-activated tumor formation. The extent of how Sufu functions is not yet understood in mammals. In an effort to identify proteins that may interact with Sufu in this pathway, over 50 candidate proteins were identified through a yeast-two hybrid screen. Through much background research, four particular proteins were selected due to their known function and location in the cell: ran-binding protein 9 (RanBP9), transmembrane 131-like precursor (T131L), COP9 signalosome complex subunit 1 isoform (Gps1), and hypothetical protein LOC67513. After performing co-immunoprecipitation assays, we confirmed interactions with T131L, Gps1 and LOC67513. These proteins have also been recognized to interact with both structural domains of Sufu, the N-terminal domain and C-terminal domain. Luciferase reporter assays have indicated that these three proteins have a role in mammalian Hh signaling through promotion of Gli activity. These experiments will hopefully help us gain better understanding of the function of Sufu and the Hedgehog pathway in the human body as well as possibly giving insight in the future as to how it may affect disease development.