Involvement of the interactions of the coiled coiled domain and Δ-coils ARNO in the localization of ARNO/cytohesin-2

Open Access
Author:
Khetarpal, Risha
Area of Honors:
Biochemistry and Molecular Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Lorraine C Santy, Thesis Supervisor
  • Chen Pei David Tu, Honors Advisor
  • Wendy Hanna Rose, Faculty Reader
Keywords:
  • ARNO
  • cytohesin-2
  • IPCEF1
  • epithelial cell migration
  • GTPases
Abstract:
Epithelial cells are typically stationary in an organism, but become motile during wound healing, tissue morphogenesis, and metastasis of epithelial tumors. Previous research has supported the role of ARF6 in epithelial migration activity. As a GTPase, ARF6 is regulated by a guanine nucleotide exchange factor known as ARNO or cytohesin-2. When ARNO is recruited to the membrane from the cytosol, it is able to activate ARF6. This research demonstrates the altered localization of ARNO with the use of a recombinant ARNO, known as Δ-coils ARNO, in which the coiled coil domain of ARNO is removed. This evidences the integral role of the coiled coil domain of ARNO in the localization of ARNO to the membrane. Furthermore, upon incubation of Δ-coils ARNO with the coiled coil domain of ARNO, an interaction was demonstrated between the coiled coil domain and the Δ-coils ARNO. This speculated interaction would block the PH domain, a membrane binding domain of ARNO, resulting in the retention of ARNO in the cytosol. This proposed mechanism is predicted to be carried out through the activity of scaffold proteins, which is also tested in this study.