Investigating Cellular Interactions Between the Rho GTPase TCL/RhoJ and Coronin Proteins

Abstract

The Rho‐family GTPase TCL/RhoJ enhances pro‐angiogenic and pro‐metastatic cellular processes; however, contributing protein interactions are not well characterized. TCL is part of the Cdc42 subfamily of Rho GTPases but has a short, unique N‐terminal amino acid sequence that is important for GTP‐loading and plasma membrane localization. Additionally, we have evidence that TCL binds vesicular membranes through a protein/protein interaction when it is GDP‐loaded. We are evaluating whether Coronin proteins selectively interact with GDP‐loaded TCL, as Coronin proteins contain CRIB motifs that bind other Rho family GTPases when they are GDP‐loaded. To determine if the Coronins co‐localize with TCL at vesicular membranes, mCherry‐fusions of the seven Homo sapiens Coronin proteins will be transfected into HeLa cells along with YFP‐tagged TCL and mutants bearing constitutively active (Q79L) and dominant negative (T35N) mutations. These TCL mutations will mimic GTP/GDP bound forms of TCL and help identify nucleotide‐dependent interactions with Coronin proteins. Coimmunoprecipitation assays will also be performed to detect interactions between Flag tagged‐TCL and myc tagged‐Coronin proteins. These results will provide additional insights into binding partners that influence the role of TCL in pro‐angiogenic/metastatic processes.Support or Funding InformationThis work was supported by Bemidji State University Biology Department and the College of Business, Mathematics, and Science. Support was also provided through the Neilson Foundation, Bemidji, MN and Regenerative Medicine Minnesota (RMM‐2017‐EP‐04).