Identification of GDP‐dependent Interactions Between TCL and Potential Effector Proteins

Abstract

TCL/RhoJ belongs to the Rho family of GTPases and has been shown to contribute to tumor‐associated angiogenesis as well as metastatic melanoma. While the role of TCL in these pathological events is becoming clearer, less is known about its biochemistry and molecular/cellular function. To better understand the cellular events controlled by TCL, experiments in our lab have focused on where TCL localizes to in cells based upon its nucleotide loading status and prenyl modifications. Using constitutively active (CA) and dominant negative (DN) mutants of TCL, we have shown that GTP‐loaded TCL localizes to the plasma membrane while GDP‐loaded TCL is more vesicular in appearance. Clearly, localization of CA TCL to the plasma membrane is also dependent on prenylation of the TCL CAAX motif as mutation of this signal sequence results in diffuse cytoplasmic localization. However, the same CAAX mutation in the context of the DN mutation lead to a marked vesicular localization. Together, our results have led us to hypothesize that TCL is specifically retained to vesicular membranes through an interaction with an unidentified binding partner, and current experiments using biotin‐ligase tags of CA and DN TCL and BioID procedures are aimed at identifying a vesicle‐bound partner protein. We anticipate that a more complete understanding of how TCL functions at vesicular and plasma membranes will help identify its potential role in vesicular trafficking in pathology‐related 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).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.