Characterising the molecular function of the Rho GTPase RhoJ in endothelial cells

Wilson, Eleanor (2014). Characterising the molecular function of the Rho GTPase RhoJ in endothelial cells. University of Birmingham. Ph.D.

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Abstract

RhoJ is an endothelial expressed Rho GTPase that localises to focal adhesions and regulates cell migration and tube formation. Previous work in our laboratory determined that RhoJ activation negatively regulates focal adhesion (FA) numbers, and interacts with the FA proteins GIT1 and β-PIX. The studies presented in this thesis aimed to characterise the role of RhoJ in modulating FA dynamics, further investigate its interactions with the GIT/PIX complex, and generate a RhoJ knockout mouse to determine its function in vivo.
Silencing RhoJ led to prolonged FA disassembly in migrating human umbilical vein endothelial cells (HUVEC), while adhesions in cells expressing a dominant active (da) mutant of RhoJ disassembled more rapidly. Interactions between daRhoJ and GIT1, GIT2 and β-PIX were identified, and the localisation of any member of the RhoJ/GIT/PIX complex to FAs was found to be dependent on each of the other components. daRhoJ expression increased levels of GIT2 protein, while silencing RhoJ reduced GIT2 Tyr 392 phosphorylation. In vivo, the growth of subcutaneous tumours was reduced in RhoJ knockout mice compared to wild type controls.
In conclusion, the data presented in this thesis show that RhoJ regulates FA disassembly, most likely in concert with the GIT/PIX proteins. This in turn influences endothelial cell migration and ultimately angiogenesis.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):